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Full text of "Alcoa aluminum and its alloys."








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ALCOA 




ALUMINUM COMPANY OF AMERICA 



PITTSBURG H o PENNSYLVANIA 



COPYRIGHT 1935 

ALUMINUM COMPANY 

OF AMERICA 



ALCOA 




FOREWORD 









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I here is a rapidly growing demand for infor- 
mation concerning the properties of aluminum 
— one of the newest of the structural metals. 

The number of alloys has grown to such an ex- 
tent that the designing engineer is sometimes at 
a loss to know which one to choose. No two of 
the alloys have identical properties and for each 
application some one alloy is best suited. It is 
also necessary to know the forms in which these 
materials are available and the sizes that are in 
commercial production. 

It is the purpose of this booklet to present in 
concise form some of the fundamental informa- 
tion concerning the alloys which are produced 
by Aluminum Company of America. 



GENERAL INFORMATION 

1 he most striking quality of aluminum, among its many use- 
ful properties, is the fact that it weighs about one-third as much 
as other commonly-used metals. This advantage is retained in 
its commercial alloys, some of which are actually lighter than 

pure aluminum. 

Combined with the low specific gravity of aluminum are many 
other desirable characteristics which have made aluminum the 
lifth most commonly-used metal today, both in point of tonnage 
and volume. Chief among these are: high resistance to the cor- 
rosive action of the atmosphere and a great variety of chemical 
compounds; high thermal and electrical conductivity; high re- 
flectivity for radiant energy, from the short wave lengths of ultra- 
violet to the longer waves of heat and electromagnetic or radio 
waves; and ease of fabrication. Aluminum can be welded by all 
commercial methods (See page 25). Its compounds are colorless 
and are without harmful action upon the human system. While 
ordinarily quite inert, at very high temperatures or in the presence 
of certain chemicals, notably strong alkalis, aluminum is a strong 
reducing agent and is used to reduce refractory metals from their 
ores and to remove gases from molten steel. 

While considering the properties of aluminum in relation 
to its various applications, attention should be called to the ad- 
vantages resulting from the lightness of the metal even in those 
cases where this quality has no direct bearing on the usefulness of 
the product. 



5 



ALCOA ALUMINUM and ITS ALLOYS « 







Comparisons of costs should be made on the finished article as 
made from the different possible materials, not on their relative 
prices per pound. Since the volume of metal commonly used will 
be substantially the same, the price per pound of aluminum should 
be divided by the ratio of specific gravities (approximately three 
for most of the common metals) when comparing the material 
costs. In addition, economies frequently result from the greater 
ease with which aluminum can be fabricated, the greater produc- 
tion and lower cost of distribution made possible by the lightness 
of the metal, and the ease with which the metal can be polished 
or otherwise finished. 

Frequently, these economies are more than sufficient to over- 
come an unfavorable cost comparison from the standpoint of 
metal value alone, as, for example, with common grades of steel. 
In such comparisons, the higher scrap value of aluminum when 
the article is finally discarded is always an advantage to be con- 
sidered in the choice of the metal to be used. 

Aluminum of commercial purity may contain up to one per 
cent of other elements, principally iron and silicon, as impurities. 
This is the grade which is commonly used, although for certain 
special applications, metal of higher purity is required. 

Commercially pure aluminum in the annealed or the cast con- 
dition has relatively low mechanical properties; its tensile strength 
is approximately one-fourth to one-fifth that of structural steel. 
The strength may be more than doubled by working the metal 
( old, that is, by strain-hardening, after the cast structure of the 
ingot has been broken down by hot working. This gain in strength 

accompanied by a loss in the ductility of the metal; the forming 
qualities are decreased as the amount of cold working is increased. 

The addition of other metals to form alloys offers another means 
of increasing the strength and hardness of aluminum. The small 
percentage of impurities in commercial aluminum is sufficient to 
increase the strength, compared with that of pure aluminum, 
about 50 per cent. 

The metals most commonly used in the production of commer- 

ial aluminum alloys are copper, silicon, manganese, magnesium, 

chromium, iron, zinc and nickel. These elements may be added 

singly, or some combination of them may be used to produce the 

desired characteristics in the resulting alloy. If the alloy is to be 



6 



» ALUMINUM COMPANY of AMERICA « 



manufactured in wrought forms, the total percentage of alloying 
elements is seldom more than six or seven per cent, although in 
casting alloys, appreciably higher percentages are frequently 
used. 

The tensile strength of the aluminum alloys in the cast or the 
annealed condition varies, depending upon their composition, up 
to values about double that of commercial aluminum. The wrought 
alloys may have their strength further increased by cold working. 
The gain in strength which results from alloying and strain- 
hardening is accompanied by a decrease in the ductility of the 
metal, although the properties which result are more than ade- 
quate for a great variety of commercial applications. 

Some years ago, the discovery was made that certain of the 
aluminum alloys, when subjected to appropriate heat-treatment 
processes, showed remarkable increases in tensile and yield 
strength and hardness. The elongation, in some instances, was 
also increased over that of the annealed alloy. The combination 
of alloying and heat-treatment processes has made available a 
series of aluminum alloys having strengths comparable with those 
of structural steel, while retaining in large measure the character- 
istic qualities of the parent metal. Both wrought and cast alloys 
which respond to the heat-treatment operations have been de- 
veloped, but the improvement is more pronounced in the case of 
the alloys in which the cast structure has been broken up by 
working the metal. 

With the development of this class of alloys, the enumeration 
of desirable qualities of aluminum may be augmented to include 
excellent mechanical properties. "Aluminum" is used here in its 
popular sense, that is, not only commercially pure aluminum, but 
the light alloys in which aluminum is the principal constituent. 
The remarkable development in the aluminum industry, in the 
past few years, must be attributed to the strides which have 
been made in the structural applications of the light, strong 
alloys. 

The change in strength which is accomplished by the alloying 
of other metals with aluminum is accompanied by changes in 
the other properties of the metal. They are seldom, if ever, the 
same in the different alloys, with the result that several alloy > 
may have substantially the same tensile strength, but differ 





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U.COA ALUM1MM and ITS ALLOYS 



« « ■ « 



widely in yield strength, resistance to corrosion, thermal and 
electrical conductivity, the ease with which they can be cast or 
fabricated, or in other qualities upon which their various applica- 
tions depend. For many purposes, considerations other than 
strength are the deciding factors in the choice of the material. 

The properties which are required in a material, as well as the 
qualities which may be sacrificed without serious handicap, vary 
widely with the use that is to be made of it. A considerable num- 
ber of commercial alloys has been developed, each of which is de- 
signed to meet the requirements of a certain type of application. 
The compromise, which is practically always necessary in choos- 
ing any material, is thus reduced to a minimum. 

The fabrication of an alloy into the products required in in- 
dustrial applications generally becomes more difficult as the me- 
chanical properties of the alloy are increased. The fabricating 
characteristics of a material are, obviously, reflected in its selling 
price, a factor which is usually of importance in the selection of a 
material. 

The ease of manufacture varies with the nature of the com- 
mercial manufacturing process; for example, some alloys having 
valuable properties may be readily rolled into plate and sheet, but 
present difficulties in the manufacture of tubing or forgings which 
would make their cost prohibitive. Other alloys may be developed 
primarily to overcome such manufacturing problems. While alu- 
minum alloys having a wide range of mechanical properties are 
available in practically all the forms in which metals are pro- 
duced, not all of the alloys are available in all of these forms. The 
tables of commercial sizes for the various commodities on pages 
55 to 89 indicate the alloys in which they are regularly manufac- 
tured. In some instances, other alloys can also be produced where 
required for specific purposes. Such cases should be taken up with 
the sales representatives of Aluminum Company of America. 



8 




WROUGHT ALLOYS 

Ihe wrought alloys of aluminum may be divided into Iwo 
classes depending upon the manner in which their harder tempers 
are produced. One class comprises the alloys in which strain- 
hardening, by definite amounts of cold work following the last 
annealing operation, produces the varying degrees of strength and 
hardness. The alloys in the other class depend primarily upon 
heat-treatment processes to develop their higher mechanical 
properties. 

While there is a wide range of tensile properties in both classes 
of alloys, the highest combinations of strength and ductility 
available in the widest range of products are to be found in the 



heat-treated alloys. 



Commercial Forms: Aluminum and its alloys are available in 
practically all of the forms in which metals are fabricated. The 
commercial sizes for some of the more commonly-used product- 
are shown in the Appendix, as well as the alloys which are most 
commonly specified for the various forms. Aluminum Company 
of America manufactures foil, flat and coiled sheet, and plate; 
bar, rod and wire; standard structural shapes; moldings and spe- 
cial shapes, both rolled and extruded; seamless drawn tubing in 
round, square, rectangular, streamline and special shapes; rivets, 
nails, screws, bolts, nuts, and other screw machine products; 
collapsible tubes; bus bar, electrical conductor cable and fittings; 
forgings; and fabricated apparatus, such as chemical equipment, 
fuel and storage tanks and shipping drums. 






9 



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ALCOA ALUMINUM and ITS ALLOYS 



« 






Reducing dead-weight without sacrificing structural strength, non-combue- 
lili' shatter- and splinter-proof AJcoa Aluminum is wid< l> used in aircraft 

< onstniction. For structure, motive power, and accessories. 








i 






4 



Special corrosion-n isl ing alloj 
n I-" ible i he i oris) r u< i ion of 

Lliin I I police patn '1 boal . 




From s to 10 inns lighter, AJcoa 

VJuminum hopper cars resist il* 

corrosion of sulfur compounds. 




& i& of tin availability oi economical special *hap< 
lent iK< If unusually irell i<> the construction of this light, 

lirn <\ 1 rain. 



Alcoa VJuminuiu 

but -■«(' sti m- 



ducing II u drag of dead-weight when er ma ■ /// motion, the 
grdi strong alloyt of ilcoa Aluminum benefit transportation in all 

its ph( v he I her on land, water or in the air. 



10 



» • » ALUMINUM COMPANY of AMERICA 



« 



« 



« 



Alloy Composition and Nomenclature: The alloys produced 
by Aluminum Company of America in the various wrought forms 
are shown in Table 2 (in Appendix, starting on page 55) with their 
nominal chemical compositions. The alloys are designated by 
numbers followed by the letler "S" to indicate that they are 
used in the wrought condition. In some few cases, the number is 
preceded by a letter to indicate that it is a composition modified 
somewhat from thai of the alloy which is designated 1>> the same 
number; for example, AITS differs from ITS in that it contains 
smaller percentages of t he same hardening elements. 

The symbol which designates the alloy composition is followed 
by one indicating the temper, but separated from it by a dash; 
for example, 53S-T, meaning alloy No. 53 in the wrought (S) 
condition with a temper designated as 4i T". 

Commercially pure aluminum, which contains up to one per 
cent of impurities and in this sense may be considered as a "nat- 
ural alloy," is designated by the symbol 2S when in the wrought 
form. 



Temper Designations: In the case of all the alloys, the cast 
ingot or billet is first worked hot to break down the cast structure. 
The hot working may be followed by cold working to final di- 
mensions. As the metal is cold worked, it strain-hardens, and it is 
usually necessary to introduce annealing operations to prevent 
excessive hardening. In the case of the softer alloys, this may not 
be necessary except as a means of controlling the amount of cold 
work necessary to produce the desired temper. 

After annealing, the alloy is in its softest and most ductile 
condition and is said to be in the soft or annealed temper desig- 
nated by the symbol "O". The hard temper, designated by the 
symbol *\H", is produced by cold working the metal the maximum 
amount which is commercially practicable for the different alloys. 

In one class of alloys (2S, 3S, 4S, 52S), tempers intermediate in 
the range of tensile strength between the soft and the hard tem- 
pers are produced by varying the amount of cold work after an- 
nealing. The standard tempers, quarter hard (J^H), half hard 
(J^H) and three-quarter hard (%H) provide a gradation of prop- 
erties sufficient for most commercial requirements. 

For these alloys, the tempers are defined by the tensile strengths 



11 



. » ALCOA ALUMINUM and ITS ALLOYS . « 



« 



which result from cold working the alloy. In the soft or annealed 
temper, the maximum strength is specified to insure (hat the an- 
nealing has been complete. For the harder tempers, the minimum 
tensile strength is specified with appropriate elongation require- 
ments to define the various tempers. 

In the case of the heat-treatable alloys, the symbol "T" is 
used to indicate that the metal is in the fully heat-treated temper 
and has the maximum strength developed by boat treatment. 

For some of the alloys (17S-T, A17S-T, B17S-T, 24S-T), (his 
lemper is obtained by a solution heat treatment followed by 
natural aging at room temperatures. The solution heat I real men I 

consists in bringing the metal to the appropriate high tempera- 
ture and quenching from this temperature in cold water. (See 
page 36 for discussion of practice and theory of (his operation.) 

Some of the alloys (25S-T, 27S-T, 51S-T, A51S-T, 53S-T) de- 
velop their full strength, i.e., their "T" temper, only if the solu- 
tion heat treatment is followed by a precipitation heat treatment. 

This consists in artificially aging the alloy at a temperature ap- 
preciably higher than ordinary room temperature (I S. Patent 
394,534). The symbol "W" may be used only with these alloys 
to designate the intermediate temper which results if they are not 
subjected to aging. 

This temper is sometimes (ailed the "as quenched" temper, but 
the name is not strictly accurate as applied to 51S-W and 53S-W, 
since these alloys undergo some spontaneous aging at room tem- 
peratures after I hey have been quenched. The properli shown 
for the "W" temper are those which result after the normal agin; 

is practically complete. Immediately after quenching, the tensih 
and yield strengths ai appreciably lower and the metal may be 
subjected to more difficult forming operations than are possible 
after it has been allowed to age. The practu i of quenching im- 
mediately before forming is sometimes used in (he case of ITS 

and 2 IS. particularly in the cs of rivets, in ordei to iak< ad- 
vantage of the better working qualities of the alloy in this condi- 
tion. The aging then proceeds in the finished a ntbly. 

Strain-hardening maj also be used a means of improving the 
mechanical properties of the heat-treatable alloys. Relatively 

-mall amount of < d work dom >n th< i alloys in the heal 
treated temper, 1 produo marked incn a their Id 



12 



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» ALUMINUM COMPANY of AMERICA « « « 



strengths. The elongation is also quite sensitive to small amounts 
of strain-hardening, the reduction in this property being greater 
for small initial reductions in cross-sectional areas by cold work 
I ban for subsequent larger reductions. However, by careful con- 
irol of the amount of cold working, the yield strength may be 
greatly improved without too great sacrifice in the ductility of 
the alloy. 

The temper which results from strain-hardening this class of 
alloys after they have been heat treated is designated by the 
symbol 4, RT": for example, 24S-RT. The increase in tensile, 
shear and bearing strengths is relatively small. 



PHYSICAL PROPERTIES 

Specific Gravity: The specific gravity of the commercial wrought 
aluminum alloys differs only slightly from that of the parent 
metal. The greatest increase in this property, caused by alloying, is 
about three and one-half per cent, and some of the alloys in which 
magnesium and silicon, either combined or separately, are the 
principal hardening elements are actually lighter than pure alu- 
minum. The specific gravities are shown in Table 4, with the 
weights in pounds per cubic inch. The weights of the casting 
alloys are shown in Table 11. 



Electrical Conductivity: The electrical conductivity of alu- 
minum is lowered by the addition of alloying elements, the reduc- 
lion varying with the nature of the element and the amount add- 
ed. Heat treatment and mechanical working also influence this 
property to a marked degree. In Table 4 will be found the elec- 
trical conductivities for the wrought alloys in their various 
tempers. 



Thermal Conductivity: Aluminum of a purity of 99.6 per cent 
has a thermal conductivity of 0.52 in c.g.s. units (calories per 
second, per square centimeter, per centimeter of thickness per 
degree centigrade), which is equivalent to 1.509 B.t.u. per hour 
per square foot per inch of thickness per degree Fahrenheit. The 
t hernial conductivities of some of the aluminum alloys are shown 
in Table 4. 






13 



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ALCOA ALUMINUM and ITS ALLOYS 



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<<. 




Structural detail showing Alcoa Aluminum sections used in constructing a 

botanical garden building. 




Above — Due to the light weight of 
this strong aluminum alloy 5-yard 
dipper, the operating speed for a 
loading cycle is the sam< as it for- 
merly was with smaller all-steel dip- 
pers, thus increasing tin- hourly 

output 4:; . 



Right — Alcoa Aluminum Alios No. 

17S-T made possible this 175-fool 

boom, which weighs, fulls rigged. 

29,000 pounds, or 17,000 pounds 
as than a standard 150-fooi steel 

boom. 




14 



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ALUMINUM COMPANY of AMERICA « « « 



Thermal Expansion: The coefficient of thermal expansion of 
aluminum is slightly more than twice that of steel and cast iron 
(See Table 6). The alloys have coefficients the same or slight l> 
less than that of pure aluminum, except those which contain rela- 
tively high percentages of silicon in which the value is appreciably 
lowered. In spite of the difference in expansion when subjected 
to thermal changes, composite structures in which both steel and 
aluminum alloys have been used have show n entirely satisfactory 

performance. 

Modulus of Elasticity; Young's modulus, which is the ratio of 
stress in strain in the elastic range, is approximately the same in 
aluminum and its commercial alloys. The average value for I hi 
constant is approximately 10,300,000 lb. per sq. in. Tin- value 
ma> be increased somewhat by relatively large additions of al- 
loying elements. In fact, careful measurements in 2 IS alio} ha\ 
given an average close to 10,500,000 lb. per sq. in. 

Because of the lower value of lhi> constant as compared with 
that of steel, it is necessary to use deeper sections in aluminum 
alloys in order to maintain the same deflection characterise 
when I hey are loaded as beams. Such redesign can be accom- 
plished to produce a strut lure having the same deflection under 
load and actually higher ultimate strength than would be ob- 
tained with structural steel, and at the same lime to realize a 
saving in weight of more than a pound for each mud of alu- 
minum alloy used. 

The lower modulus of elasticity is an asset when impact loads 
are to be resisted since, other things being equal, the lower the 
modulus the greater the ability to absorb energy without perma- 
nent set. The lower modulus is also advantageous in reducing 
stresses produced b> misalignment, settlement of supports, or 
other fixed deflections, accidental or intentional. 

Mechanical Properties: Typical average mechanical properties 
f the various wrought allo\^are shown in Table 10. These valu< 



may be used in comparing the alloys with each other, or with 
other materials, since typical properties are commonly quoted. 

Purchase specifications are based on the minimum values for 
those properties which are regularly determined in the routine 



1 



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ALCOA ALUMINUM and ITS ALLOYS 



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control of commercial manufacturing operations. Tables showing 
these minimum properties which can be guaranteed for the va- 
rious commodities are also included in the Appendix. 

It will be observed that the minimum properties guaranteed 
for an alloy are not the same in all commodities or in all sizes of a 
given product. Since the type and dimensions of the test specimen 
specified by standard testing practices vary with the nature of 
the product or with its dimensions, some of the variations in the 
guaranteed properties represent differences in the test rather than 
fundamental differences in the properties of the metal in the 
various commodities. In the case of rod which is tested in full 
section, the elongation is measured over a gauge length equal to 
four time- the diameter of the rod in order to compensate for 
the effect on this properly of the variable cross section. 



Strain -Hardened Alloys: It has been slated previously that the 

production of the harder tempers of certain of the aluminum 
alloys is accomplished l>\ strain-hardening, the different degree 
of hardness being obtained by varying the per cent of reduction 
1>\ (old work after the final annealing operation. 

In the manufacture of sheet, tubing and wire, it is standard 
practice to work the metal cold after the cast ingot has been 
broken down hot to produce the hot mill slab, the tube bloom or 
I he rod, respectively. In these eases, the amount of reduction 
i an be carefully controlled b\ proper selection of roll settings or 
f < and mandrel sizes. The production of intermediate temper 
involves only the annealing of the stock at the proper size to 
produce the desired amount of strain-hardening by the cold fin- 
ishing operations. The onl\ limitation is that the final size shall 
be enough smaller than the hot mill slab, the tube bloom or I he 

rod to permit the necessary reduction to develop the desired 

temper. 

In tie manufacture of extruded products and in the rolling of 

plate, rod, bar and shapes, the metal is regularly produc 1 from 
a hot ingot and is reduced to the (J- -ired size without intermediate 
cooling. Where closer tolerances or special surface finish is re- 
quired, rod and bar ma\ be lied oversize b> an amount suf- 
ficient to permit a (old finishing operation. The amount of cold 
working is chosen from the standpoint of producing the desired 



16 



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» ALUMINUM COMPANY of AMERICA « « « 



finish and, except in the smaller sizes, does not greatly alter the 
mechanical proper t ies. 

During the process of manufacture of these products, there is 
some cooling of the metal, the amount of cooling being greater, 
the thinner the finish size of the material. There is some strain- 
hardening of the metal, the strength varying from that of the 
annealed alloy for heavy sections to that of the half or three- 
quarter hard temper for small sizes of rod or bar. For any given 
size of product, the manufacturing conditions are fairly uniform, 
and succeeding lots of material will have substantially similar 
properties. 

While it is possible in some cases to produce these products in 
the strain-hardened tempers by adopting special manufacturing 
methods, it is preferable to obtain the higher strengths by choos- 
ing a harder alloy instead of specifying a harder temper, the pro- 
duction of which may entail prohibitive manufacturing costs. 

Extruded shapes are produced by forcing the solid metal 
through a die having an aperture to produce the desired shape. 
Since the alloys are more plastic at elevated temperatures, these 
products are produced hot. Depending upon the alloy and the 
nature of the section, there is some variation in the extrusion 
conditions and consequently in the mechanical properties of the 
shapes as extruded. In the case of 2S, 3S, 4S and 52S, the guaran- 
teed tensile strength of extruded shapes cannot be higher than 
that of the annealed temper of the alloy, although higher values 
up to those for the half hard temper are frequently obtained. 

Extruded shapes in the heat-treatable alloys are usually heat 
treated to develop the properties of their heat-treated tempers. 
In the Appendix, a table is included showing the approximate 
tempers of representative sizes of bar, rod, shapes and plate in 
the various alloys for which these products are supplied "as fab- 
ricated" (i.e., as rolled, as cold finished, as extruded) (See Table 
39). In general, the ratio of yield strength to ultimate tensile 
strength is slightly lower in the "as fabricated" products than it 
is in the corresponding temper produced by cold working. 

Choice of Alloy: The choice among the relatively large number 
of wrought aluminum alloys depends upon the qualities which arc 
required for the particular application. While the mechanical and 



17 



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ALCOA ALUMINUM and ITS ALLOYS 



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One of the world's largest dump bodies, made of the light, strong allo\s of 
AJeoa Aluminum, hauled 25-ton loads up 25% grades at Boulder Dam. 




\ new al uminum floor system saved 750 tons of dead-weight and added 

another quartei century to the life of this bridge. It abo taved the lax- 

payen a million and a half dollars. 



18 



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ALUMINUM COMPANY of AMERICA « 



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physical properties are shown in the tables contained in the Ap- 
pendix, the problem of making the best choice may be facilitated 
by a brief discussion of the alloys. In order to simplify the form 
of expression, 2S will be referred to as an "alloy" although it is 
commercially pure aluminum; it is an alloy only in the sense that 
it is aluminum containing up to one per cent of other elements as 
impurities. 

Commodities, such as sheet and plate, are available in prac- 
tically all of the alloys except a few which were developed pri- 
marily for the production of forgings, machining rod or for other 
specific purposes. Experience has shown that the commercial re- 
quirements for tubing, rod, bar and structural shapes can be met 
adequately by a more limited group of alloys and the problems 
of manufacture as well as the choice by the user are thereby 
simplified. 

The alloys 2S, 3S, 4S and 52S comprise the group in which the 
harder tempers are produced by strain-hardening. They are 
listed in the order of increasing tensile strength for a given 
temper. For applications in which ease of forming by drawing, 
spinning or stamping is of paramount importance, and the re- 
quirements of the service which the part must perform do not 
impose the requirement of high strength, 2S or 3S is commonly 
specified. Because of their greater ease of manufacture, these 
alloys offer the advantage of lower cost. In any given temper, 3S 
is slightly more difficult to form than 2S. The choice of alloy and 
of temper will depend upon the severity of the forming opera- 
tions. For some uses, the greater strength and stiffness of 3S 
make its choice desirable in spite of the slightly greater fabricat- 
ing difficulties. Both 2S and 3S sheet are used in the manufacture 
of drawn cooking utensils, bottle and jar closures, cosmetic con- 
tainers, and a variety of similar articles. Depending upon the 
depth of the draw, the temper of the sheet may vary from soft 
to three-quarter hard; the half hard temper is frequently speci- 
fied. The final choice must be based on the trial of samples on the 
tools which are to be used in commercial production. 

The alloys 4S (U. S. Patent 1,797,851) and 52S are much 
stronger than 3S. In the quarter hard temper (4S-^H, 52S-^H), 
their mechanical properties are appreciably higher than those of 
3S in the hard temper (3S-H). Although 52S has a higher tensile 



19 



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ALCOA ALUMINUM and ITS ALLOYS 



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strength than 4S, its yield strength is somewhat less in the strain- 
hardened tempers, and its forming qualities are decidedly better 
lhan those of the latter alloy. This fact, together with its ex- 
cellent resistance to corrosion and its high endurance limit, has 
caused the demand for this newest of the aluminum alloys to 
exceed that for many of the older alloys. 

In their harder tempers, both 4S and 52S have yield strengths 
( omparable with that of 17S-T, the most widely used of the heat- 
treatable alloys, although their tensile strength and elongation 
are not so high. In the form of plate, rod and bar, which are not 
regularly produced in the strain-hardened tempers, these alloys 
make available mechanical properties intermediate between those 
of 3S and those of the stronger heat-treated alloys. 

Heat-Treatable Alloys: The heat-treatable alloys present a 
wide range of properties to meet the varied requirements of the 
structural applications of aluminum products. The oldest and 
most generally used is ITS. It is manufactured in practically all 
of the forms in which metals are fabricated. A modification of this 
alloy containing lower percentages of the alloying elements, 
AITS, was developed to provide a material which would with- 
stand more severe forming in the heat-treated temper than is 
possible with ITS. The mechanical properties are lower, but it 
finds some use where the higher strength is not required. 

The alloy 51S in its fully heat-treated temper (51S-T) (U. S. 
Patent 1.172,739) has a yield strength higher than that of 1TS-T. 
but it- tensile strength and elongation are appreciably lower. In 
this temper, it is capable of only limited forming, but it is readih 
workable in the quenched temper (51S-W). Difficult forming 
operations may be performed on the alloy in the quenched temper 
31S-W ) after which the part may be aged at elevated tempera- 
tures to develop the higher strength of 51S-T. Because of its 
greater ease of fabrication, it is sold at a price lower than that 
of ITS and for many purposes its properties are adequate. 

The allo> 21S makes available a material having even highei 
mechanical properties than those of ITS. The tensile and yield 
strengths of 24S-T are approximately 8,000 lb. per sq. in. higher 
lhan those f 17S-T; in the case of the yield strength this repre- 
sents an increase of approximately 25 per cent. This i of par- 



20 



„ 



\LUA1INUM COMPANY of AMERICA 



r 



Licular interest since it makes possible the use of Alclad 24S 
sheel (See page 31), with higher design factors than are possible 
with the use of bare ITS sheet. This alloy is finding increased use 
in aircraft construction and in other structures where the maxi- 
mum strength combined with the minimum weight is required 

Strain-hardened after heal treatment, this alloy (24S-RT) has th< 
highest strength of any of the commercial wrought aluminum 

alloys. 
For architectural us.', an alloy was desired having the maximum 

resistance to the corrosive action of the atmosphere from the 
standpoint of retaining both its mechanical propertie and it 

urface finish. The alloy should have good forming qualities and 
should have tensile and yidd strengths superior I" those of IS 
alloy in the form of extruded or rolled sections To meel ill re- 
quirements, the alio} 53S (U. S. Pateni l,'H 1.077) wasdeveio] d. 
In a short lime the use of the alloy extended beyond the applica- 
tion for which it was originally developed becau-e of its excellent 

eneral qualities. For maximum resistance to orrosion (compar- 
able with that of 2S) either 53S or, in the case of sheet, S 3, is 
recommended where their mechanical properties ;ire adequate. 
W here higher strengths are required, together with maximum re- 
sistance to severely corrosive conditions, Aid i 1 L7^ and Alclad 

2 IS are available in the form of sheet, plate and wire. 

27 S-T Alloy: While 27S-T is listed as commercially available 
only in the form of forgings, it has also found considerable us< 

in other wrought forms. Its tensile and yield strengths and hard- 
ness are higher than those of 17S-T, as is seen by reference 
Table 10. Its resistance to corrosion is comparable with thai 

of 17S-T. 

While not in regular production in all of the mills, other forms 

such as sheet, plate and structural shapes have been produced 

for specific projects involving sufficient material to justify their 

special manufacture. Sales representatives of t he < ■ ■mpain should 

be consulted in relation to applications for which the higher 

properties of this alloy are indicated as required for the success 
fill use of aluminum alloy construction. 

Forgings: The alloy most extensively used in the manufacture 
f forgings is 25S (1 . S. Patent 1,472,738). This alloy in its full} 



r< 



21 



» » 



» ALCOA ALUMINUM and ITS ALLOYS 



« « « 



heat-treated temper (25S-T) has mechanical properties very near- 
ly the same as those of 17S-T. It is more easily worked at ele- 
vated temperatures, however, and for this reason, it is generally 
used for forged parts. For some forgings, 17S-T is specified be- 
cause of its greater resistance to severely corrosive conditions. 
Forgings in 27S (U. S. Patent 1,472,738) alloy have a tensile 
strength about ten per cent higher and a yield strength more 
than fori y per cent higher than either 17S-T or 25S-T. This alloy 
is used in preference to 2 IS for the production of forgings because 4 
of its superior hot working qualities. The mechanical properties 
of 1 1S-T are higher even than those of 27S. The alloy V51S can be 
forged even more easily than 25S and is therefore used for large 
and intricate parts which cannot be produced in the harder al- 
loys. Because of its lower cost, it is also used for forgings in 
which higher mechanical properties are not required. 

The alloy 70S (U. S. Patent 1,924,729) is likewise used where a 
lower cost product is desired. For forged parts, such as pistons, 
in which the retention of strength at elevated temperature is es- 
■ ni.ial, the alloys 32S (U. S. Patent 1,799,837) and 18S are used. 
In addition to good mechanical properties at the working tem- 
peratures of interna] combustion engines, 32S has the advantage 
of a lower coefficient of thermal expansion than that of other 
\\ r ought aluminum alloys. 



Extruded Sections: The extrusion process makes possible the 

production of shapes which have been designed to facilitate the 

erection of the structure in which lhe\ fire used, and in which 

the metal is disposed more efficiently with relation to the stress* 

which it must withstand than is possible in standard rolled slruc- 

il shap The use of such extruded sections has greatly simpli- 
fied aircraft design and has contributed largely to the economic 

success of lightweight railway car construction. The savings in 

ere lion cost resulting from the use of special extruded shapes 

has gone far in offsetting the higher cost of aluminum alio) as 

tmpared with structural steel. Th< shapes also have marl. 

ossibleeven greater saving in weight than could be accomplished 
v the substitution of standard rolled structural shap of 
aluminum allo> for similar sections in structural steel. 



22 



» , » ALUMINUM COMPANY of AMERICA « « « 

Forming: Commercially pure aluminum, 2S, is outstanding for 
I he ease with which it can be drawn, spun, stamped or forged. 
Starting with the metal in its annealed temper, articles requiring 
several successive drawing and spinning operations may be made 
without the necessity of any intermediate annealing. Since the 
alloys are less ductile than the pure metal, they require more 
liberal radii for bends and are capable of withstanding less severe 
forming. However, there is a considerable range of fabricating 
qualities among the various alloys in their different tempers, 
from 3S-0, which is only slightly less ductile than 2S-0, to 51S-T, 
which is not used where appreciable amounts of forming are re- 
quired. 

The alloys 2S, 3S, 4S and 52S cover a wide range of mechanical 
properties in their various tempers. Since their harder tempers are 
obtained by cold working during the process of manufacture, the 
amount of forming which can be done on them is greater, the 
softer the temper. For many drawing operations, the half hard 
temper retains sufficient ductility for good working qualities even 
in 4S and 52S, and some less severe draws are successfully ac- 
complished with these alloys in the hard temper. 

Aluminum alloys are frequently fabricated on tools designed 
for use with other metals. There are, however, some differences 
in fabricating practices, a knowledge of which may be helpful in 
more difficult forming jobs. In drawing or stamping operations, 
successful results may depend upon the choice of the proper lu- 
bricant. The light lubricating oils, marketed under the designation 
"metal oil," are most commonly used in large scale operations. 
The best lubricant is tallow, mixed with a small amount of mineral 
oil, but because of its greater cost and the greater difficulty of 
applying it to the blank and removing it from the finished work, 
it is used only on more difficult operations for which metal oil 
does not prove successful. 

The surface finish of the tool also exerts considerable influence 
on the results. Tool steel with polished surfaces may be required 
for more difficult draws of the harder alloys, while for many jobs, 
cast steel or even cast iron tools are satisfactory, provided the 
number of parts which are to be made is not too great. 

In forming aluminum alloys, it is necessary to recognize their 
characteristic properties. The chief requirement for successful 



23 



» » » 



ALCOA ALUMINUM and ITS ALLOYS « « « 



working is that the tools shall permit a suitable radius for bend- 
ing and drawing operations. The radius which is required varies 
both with the grade of the alloy and with the thickness of the 
material. The radius of a bend will also depend to some ex lent on 
the type of bending equipment which is used. Frequently, a small 
change in the tools has been found sufficient to obviate the ne- 
cessity of choosing a softer temper or type of alloy. In some cases, 
(his change consisted only in the slight rounding of a sharp edge 
or merely a polishing operation to improve the surface so as to 
prevent the metal from flowing into scratches or flaws in the 
tools, which action would cause I he metal to tear. In certain 
difficult forming operations, it may be necessary to resort to 
several successive draws with intermediate annealing, starling, 
of course, with annealed material. 

Table 5 is intended as a guide* in the choice of a suitable ma- 
terial or of a proper forming radius, not as a tabulation of definite 

operating limits. The final choice of the alloy or of the working 
radius should be based on a trial under the conditions to be used 
in production. The relati\e ease of forming is also affected by the 
nature of the forming process. While experience in handling these 
alloys makes possible some prediction as to the material which 
may be used, the final answer must be obtained by actual trial 
"1 different materials on the tools. 



Hot Forming: By raising the heat-treatable alloys to suitable 4 
•mperatures, it is possible to form them around much smaller 
tdii than are possible at ordinary temperatures. By working at 

a temperature around 10()°F., there is considerable improvement 

in their forming characteristics. Provided the metal is not held 
at this temperature for too long a time, preferably not more than 
a half hour, there is no appreciable loss in mechanical proper- 
ties. While there is some lo in corrosion resistance (See page 
29), it is not serious, since hot forming is used onl\ with heav> 
actions. 

Heat-treatable alios plate can be formed into angl< and other 

^hai - b> heating the metal and forming it in die-. For an i lass- 
of material, the best working temperature is in the heat- 
treatment range. In the-' <a the chilling of the i tal in the 
steel dies may constitute a satisfactory quench (1 8- Patent 



21 



» » » ALUMINUM COMPANY of AMERICA « « « 

1,751,500), such that the mechanical properties of the heat- 
treated temper will be developed in the finished part after a suit- 
able aging. I n some cases, the metal must be formed at a tempera- 
ture lower than that required for heat treatment. The advantage 
of quenching in the dies to avoid warping may be obtained by 
reheating the formed section to the heat-treating temperature 
and replacing it in the dies instead of quenching in water. Natural 
aging or precipitation heat treatment, as may be appropriate for 
the alloy, will then develop the full properties of the metal. It 
must he emphasized that die quenching can be relied upon to give 

satisfactory results only in case the die is of such a character that 
llirre is intimate contact with the metal which is being formed. 
The dies must also be of sufficient size bo have adequate heal ca- 
pacity to absorb the heat from lheallo> and bring it promptly to 
mom temperature. 

Welding: The wrought aluminum alloys are joined by welding 
as a common commercial practice. Torch, arc, or resistance weld- 
ing are applied as the parts may require. The technique of weld- 
ing aluminum differs from that used on steel, bul is readily n 
tered with a little practice. 

Because of the oxide film which forms on an exposed surface 
it is necessar> to use a flux in torch or arc welding aluminum. 
For arc welding, a llux-coated rod is used to advantage. When 
welding the common alloys by either of these processes, a welding 
rod of 2S or of the same composition as the alloy which is being 
welded is often used, although an aluminum alloy r<»d containing 
five per cent of silicon is more easily handled and gives better 
results in complicated welds. This latter rod is recommended for 
most applications in the welding of the heat-treatable alloys. 

Butt, lap and fillet joints are made by torch welding, using 
either the oxy-hydrogen or the oxy-acetylene flame, with com- 
parable facility to similar joints in steel. 

There are some limitations to the applications of arc welding. 
However, butt joints are readily made on material I bicker than 
about Hi inch. This process possesses the advantages of greater 
speed and of less distortion of the part as compared with torch 
weldins; also, the effect on the structure and temper of the parent 
metal extends a smaller distance from the joint. 

25 



» » ALCOA ALUMINUM and ITS ALLOYS 



« 



« 



« 




Above — These 2300-gallon alumi- 
num milk transport tanks enable 
the operator to carry 200 gallons 
mi * \n application of alujuinum 
in the Dairy Industry. 



Might — All-aluminum rotary dis- 
tributor for applying sewage liquid 
1 1 » circi r trickling liltci IhmIs. The 
com on resistance of aluminum 
interests the sanitary engineer. 





Each of these thirty-nine be* i tanks is tall enough to span three floors of a 
modern brewer) and big enough Lo bouse your automobile. Unaffected h> 

beer, aluminum guards its goodness. 

[Icoa Aluminum is non-corUarninaling, non-toj , forever glerik 
The facility of fabricating aluminum — handling, forming, welding, 

n I (tig. finishing — is demonstrated by the many large-scale ap- 
plications. The allays of Alcoa Aluminum are strong, yet light* 



26 



» y> 



ALUMINUM COMPANY of AMERICA « « « 



Some general considerations should be taken into account in 
designing parts containing welded joints. The common alloys 
after welding are annealed for a short distance from the weld. 
Consequently, the design stresses for annealed alloy should be 
applied. The metal in the weld has a cast structure having about 
the same strength as the annealed metal, but less ductilil y. If the 
weld head is left as welded, the joint is usually stronger than the 
adjacent metal. Grinding of the welds will reduce the strength of 
the joint somewhat; but hammering thorn will generally accom- 
plish the same purpose as grinding, without the sacrifice in 
strength. 

Heating the strong alloys tends to destroy the effects of prior 
heat treatment. The annealing temperature range is exceeded in 
the metal adjacent to the weld and the rate of cooling in the air 
is fairly rapid, consequently, its strength is usually intermediate 
between that of the fully-annealed alloy and that which would 
result from the solution heat treatment. The change in the temper 
of the metal resulting from the heating also has an adverse ef- 
fect upon its corrosion resistance. The loss in these properties 
can be partially recovered by reheat treatment or by performing 
the welding operations before heat treatment where this plan is 
feasible. Where the joint is depended upon for maximum effi- 
ciency, torch welding, and, in many cases arc welding, cannot 
be considered equal to a well-designed mechanical type of joint. 

Resistance Welding: Resistance welding, embracing spot, seam, 
and butt welding, may be employed in the fabrication of alumi- 
num in a manner similar to that used for other materials. Due to 
the entirely different physical characteristics of aluminum, the 
technique and equipment employed will differ considerably from 
that used for steel. In some cases, however, equipment used for 
steel may be modified or added to in order to provide excellent 

t 

results when used with aluminum or its alloys. 

In addition to the required changes in equipment, several 
limes the electrical capacity is required for aluminum as com- 
pared with a similar resistance weld application in steel. 

Liquid or gas-tight tanks may be conveniently fabricated by 
means of seam welding, the weld in effect consisting of a succes- 
sion of spot welds so closely spaced as to overlap and provide a 



27 



# » 



, ALCOA ALUMINUM and ITS ALLOYS « 



« « 



continuous seam. The operation is entirely automatic and com- 
mercially practicable. 

Spot welding may in many cases be used to replace rivets with 
decreased cost and an improved mechanical result. 



CORROSION RESISTANCE 



The corrosion resistance of a material is a relative term and de- 
pends upon a comparison with other metals or alloys of the same 
metal. None of the commercial metals is immune to all conditions 
to which structural materials are exposed. There is always the 
possibility of overstressing the dangers of corrosion with the re- 
sult that the prospective user is deterred from employing the 
metal where there is no occasion for concern. On the other hand, 
if the possibi 1 i t y of trouble is minimized, metal failures may result, 
which could ha\e been avoided by simple protective measures. 

Aluminum is highly resistant to atmospheric corrosion and to 
a considerable number of chemicals. In general, there is some loss 
in this property as other elements are added to form the alloys, 
although the amount of this effect varies greatly depending upon 
the elements which are added, their percentages, and the condi- 
tion of the alloy as regards heat treatment. 

Commercial aluminum contains, as a maximum, one per cent 
of impurities. This metal, designated 2S when in the wrought 
condition, is widely used because of its high resistance to ordinary 
atmospheric conditions. Contrary to the general statement pre- 
viously made small additions of manganese, magnesium, o 
chromium to commercial aluminum have practically no adverse 
effect on the resistance of the metal to most forms of corrosion. 
The alloys 3S and 4S behave practically the same as 2S under 
imilar conditions of exposure. The alios 52S appear- to be more 
resistant to attack than 2S, both from the Standpoint of the re- 
tention of its mechanical properties and of its surl e appearance. 

Considerable study has been made on the effect of the temper 

of these alloys on their resistance to attack. Jn general, it may 
be stated that any difference in this proper! > as a result of strain- 
hardening an* jess than the small differences which are normally 

| 

to be expected from one lot to another of commercial materials 

Unless it is desired to retain a bright, highly-polished stirfei i 



28 



9 



/ 



\Ll MINI M COMPANY of AMERICA « « « 






these alloys are generally used without miy protection other than 
the usual preraution to avoid electrolytic action from contact 
with ;» dissimilar metal. I nder severe conditions of exposur< such 
;i^, 1 1 1 ; i > prevail on shipboard or where the metal Is in contact 
with wood or oilier absorbent material continually in Up- pre i< • 
of moisture, a protective coal of paint is desirable as an added 
precaut ion. 

Va a class, ihc heat-treat al>le alloys are more susceptible i 
attack than are the alloys which have just been considered. The 
alio) 53S is .in exception since in all of its tempej its resistance to 
corrosion is comparable with that of 2S. 

The heat -treatable alloys are in their most re istant state when 
lhr> haw been subjected to solution heat treatmenl followed 
liv aging at ordinary temperature In this condition, there i 
little difference in the corrosion n i nice of the alloys other than 



1 Ik it shown by 5 IS. Such differences as have b n obsei wed would 
indicate that 51S-W is slightly superior and 25S-YV slight I) in- 
ferior to 17S-T, U7S-T, B17S-T and 24S-T, which hai ib- 
stantiall) th<- same resistant e. The strain-hardening of 17S T and 

2 IS-T, lo produce their "RT" temper, does not have an) harmful 

effect oil I heir C< HTOSN '11 resist tine. 

[f the alloys arc heated al temperatures much in exc< I tl 
boiling point of water for an) considerable length of time ter 
they have been quenched, their resistance to don 

impaired, although the extenl of this effed ma) v ary with diffei 



1 * * 

mi alloys. Such heating is necessary to develop the maximum 
properties of 53S-T, 25S T and 51S-T. Their i orr< rion resistan* 
is lowered when compared with that in the "W temper, the rela- 
tive effects being indicated in the order in whi b the) are lis I. 
In 53S, the loss is so slight that the little difl e in the re- 

sistance of 53S-T and 53S-1R can scarcely be det( ted !■ ih 
methods of corrosion testing. II' IT — - - 1 \ ! 5-T, B17S-1 and 
24S-T are heated under the sam< conditions their resistan is 
serious!) impaired, but such treatment is d i necessary to de- 
velop their full properties. Vt times, baked enamel finishes ha\ 
been proposed as a means of protecting thes< illoys. It isques >n- 
able, however, whether the improvement in the prot ii v it 
is sufficient to compensate for the deci tse in the resistan >f 
the underlying metal. 



29 



» 



» 



ALCOA ALUMINUM and ITS ALLOYS « 



« 




\ bo . e — Fabricate >n i«< h- 

nique was an important 

tor in this ins ta Hal ion of 

n< \s escalators. Eas^ i< i 

for ru . \ It oa \ 1 u m i n u in 

w* I'U beautifully . assembles 
economically . \on -rusting 
in thr moisture-laden at- 
m pher these escalator 
inge are treated 1>> the 
Murnilite Prot ess. Th<\ 
n ill not smudge stain nor 

I a I nish. 



Right 



Mumirmm <\<><>\ b 



representath e of intricate 
and elaborate design <n 
readily <u^\ in al uminu m 

I >thei qunlii ies tbat rvroin- 

mend aluminum for archi- 
tectural ornamentation are 
lightweight . strength, n - 
ststanoe to corrosion, and 
easj irorkability. 




30 



, AH MINUM COMPANY <>f AMERICA 






Experience shows that aluminum alloys an* properly <l ribed 
.s corrosion-resistant materials. In many of their applications 
they arc used without any protective coating, but under aevei 
corrosive conditions, protection may be desirable. 

The efficacy of protective paints on aluminum alio depends 
mainly upon the composition of the paint, upon the preparation 
of the aluminum surface before painting, an. I upon ihe inh<-ni 
resistance of the alloy. For Bervice undei ordinary aim pheri< 
conditions, ii is usually sufficient to clean the dirt and gr< i i 
from the surface with ;« chemical cleansei which cleans with 
( ,nl\ uperficiai attack oi the aluminum surface I sir - >lvenl 
is less desirable bul may k r is iatisfactor) ' ults ''"' "''•' 
conditions where the pari is to be kepi wet or ubje< ted I I h 
humidity for extended periods, as, for exampl< in seap in< 
anodic coating of the aluminum surface i idvanta ous in pi 
moting the adhesion of the paint md in in i ing the prot 
tion of i he aluminum alio) . 

Experiments have indicated that aluminum paint, mad< I 
mixing aluminum bronze powder or pa with a suital yn 
thetic resin varnish vehicle am- ml* excellent prote< tion I he u 
f a primin coal containing zinc chroma te m a) be adi inta 
for service under conditions of severe exposure V\lmn the nn il 

is continual!) subjected to moisture, s the insid I p <" n 
or seaplane floats, bituminous paints h< iven d ervi 
Hie bituminous paint ma^ be covered t«> adsania 

aluminum painl . 

Alclad Products: " U lad" is the regist d trade-rn I 

Mununum Company >>f \meri< s to identify alio) products of 
ceptional corrosion resistance in which this prop t) im i d 
b) means of a surface laser of aluminum of high purits i >p< 
cial aluminum alloy, alloyed and integral with tbe< ore I thicl 
ness of the surface metal is so chosen as to retain, in the resultant 
product, the maximum physical properties consistent rith ade 
quate protection of the alto) core In the common!) thi< k- 

nesses of Uclad LTS-T ami Uclad 24S-T sheet, the nsil( m«l 

yield Strengths are approximates ten per cent lov r than t 

sallies for the uueoated alios- 

It is noteworthy that the coating not out) P*** Ihe i 



' \ 



31 



» » » 



\LCOA ALUMINUM and ITS ALLOYS « « « 



which it covers, but by electrolytic action, prevents attack on the 
sheared edges of the sheet or other sections of the base alloy 
which may be exposed by scratches or abrasions. Ordinary ITS 
alloy rivets, used to join Alclad sheet, are likewise afforded con- 
siderable protection because of this electrolytic effect. Such pro- 
tection is accomplished at the expense of some solution of the 
metal surface layers. Under continued exposure to sea waler, 
corrosion products may accumulate on the surface of the sheet as 
a result of I his action. While (he appearance of tin 1 metal may be 
unsightly, mechanical test specimens taken from the sheet show 
that the base metal has not suffered loss of mechanical properties. 
Willi proper cleaning the 1 appearance of the surface can be re- 
slored without removing the surface metal upon which (he pro- 
lection depends. 

Test specimens of Alclad sheel, subjected to the standard sail 
^1 »ra> lest for a period of five years, ha\e shown no loss in me- 
chanical properties. Except for some solution of the pure metal 
layer near the machined edges and in a few isolated spots, the 
sheet appeared bright. \ ri\eled tensile tesl specimen in which 
ordinary 17S-T rivets were used to join the Alclad sheets, had 
(he same strength after three years' exposure to three and one- 
half per cent sea salt spray, as the control specimen which had 
been carefully stored. 

In certain cases where resistance to surface abrasion must be 
nsidered, as in the case of wire, the surface laser may be an 
alio} which is harder than the pure aluminum, but which ha 

excellent corrosion resistance; it is also anodic to the underlying 
strong alloy, and therefore renders electrolytic protection in the 
ame manner as the pure aluminum surface. 
Sheet and plate are available in Alclad 17S and Alclad 24S in 

II the tempers in which the base alloy is supplied. Alclad ITS 
wire is manufactured with I he corrosion-resistant , hard, alioy- 

surface. Other Alclad products are in proc« of development. 

Alclad sheet is extensively used in tie- aircraft industry. Tie 
metal-clad dirigible airship. ZMC-2. made for the I nited State 
Navy, has Uclad 17S-T sheet for the outer shell. Uthoughonlj 
0.0095 of an inch in thickn* . and unprotected, test unples from 
this shell showed no deterioration after five i ire of ervia Somi 

of the leading manufacturers use Alclad sheet in various parte of 



32 



» 



» » ALUMINUM COMPANY of AMERICA « 



« « 



their planes. For most types of service, it is not necessary to paint 
Alclad sheet ; but for seaplane floats and other applications where 
corrosion conditions are unusually severe, a protective coating 
of paint may be found necessary. The surface of Alclad sheet may 
be anodically treated, prior to painting, in order to obtain the 
maximum adherence of the paint. 

The use of Alclad sheet to replace the plain sheet of the same 
alloy sometimes requires the use of slightly heavier gauges to 
compensate for its lower tensile properties. This increased metal 
thickness does not necessarily represent a corresponding increase 
in weight of the finished structure, since the weight of the pro- 
tecting paint film, which is usually applied to the uncoated sheet, 
may be comparable with the added metal weight, particularly 
in the case of the thinner gauges commonly used in aircraft. The 
substitution of Alclad 24S-T for uncoated 17S-T will actually 
permit a saving in weight without any consideration of the w eight 
of the protective paint film used with the latter material. 

It should again be repeated that the corrosion problem is large- 
ly dependent upon the condition of exposure. All of these alloys 
are used in a considerable variety of applications because of their 
satisfactory performance as regards retention of their surface 
appearance and mechanical properties. 

The nature of the section also has considerable bearing on the 
suitability of the different alloys. In aircraft construction, light- 
ness is essential; efficient design requires the use of thin, highly- 
stressed sections with the minimum factor of safety. For such use, 
ITS, 24S, Alclad 17S and Alclad 24S are recommended in the 
heat-treated (T) or rolled after heat treating (RT) temper. 

For thicker sections such as forgings and shapes, some of the 
other alloys are generally used with entirely satisfactory results. 
Should any superficial surface corrosion occur, its effect on the 
strength of the part is not appreciable and can be removed with- 
out impairing the satisfactory performance of the part . 



ANNEALING PRACTICE 

The strain-hardening which results from cold working aluminum 
alloys may be removed by annealing, i.e., by heating to permit 
recrystallization to take place. The rate at which recrystalliza- 



33 



» » 



ALCOA ALUMINUM and ITS ALLOYS « 



« 




Over i00 f < I miles of aluminum < able, strrl reinforced, fins Inrn used foi 
Lransmitting electrical energy in the United Nates alone, [ts high strength- 
weight ratio gi es an ex! ra fai I or of mc« hani< a I safet >. 




\! 



\l 



coa \iuminun bus bare pr 

i- lif<-. an i < m -) in operat ion and 

I to work. 




> 



{ hannel conductor, for hca\\ cur- 

rents, will allow greater distance 
between the support*. 



.j \ 



» 



ALUMINUM COMPANY of AMERICA 



tion occurs is greater, the higher the temperature and the more 
severely the metal has been worked before it is annealed. Com- 
plete softening is practically instantaneous for 2S and 52S at 
temperatures in excess of about 650°F., and for 3S and 4S at 
temperatures of 750°F. or higher. Heating for longer times at 
somewhat lower temperatures will accomplish similar results. 
Provided the metal has reached the instantaneous annealing 
temperature, the exact temperature is not critical, although it is 
desirable that the recommended values shall not be too greatly 
exceeded. The rate of cooling is also not important, all hough too 
rapid cooling may impair the flatness of the material. 

In the case of the heat- treatable alloys, greater care is required 
in the choice of annealing conditions. The metal must be raised 
to a temperature which will permit recrystallization in order that 
the strain-hardening shall be removed. On the other hand, the 
temperature must be maintained as low as possible in order to 
avoid heat-treatment effects which would prevent complete soft- 
ening of the alloy, or else the cooling rate must be so slow as to 
counteract the effect of such heating (See Solution Heat Treat- 
ment, page 36). 

Heating these alloys to 650°F. is sufficient to remove the strain- 
hardening which results from cold working. This temperature 
should not be exceeded by more than ten degrees, nor should 
the metal temperature in any part of the load be less than 630°F. 
The rate of cooling from the annealing temperature is not im- 
portant if the maximum temperature limit has been observed, 
but slow cooling to a temperature of about 450°F. is a desirable 
precaution in case any part of the load may have been heated 
above this temperature. 

This annealing practice, in addition to removing the hardening 
effects of cold working, also removes most of the effects of heat 
treatment when applied to metal in the heat-treated temper. For 
many purposes, this practice may be used to anneal the alloys in 
the heat-treated temper, provided the maximum degree of soft- 
ness is not required for the forming which is to be done. 

For more severe forming, which requires that the metal be in 
its fully-annealed condition, the following process must be used 
for metal in the heat-treated temper. The alloy is heated at a 
temperature of 750°F. to 800°F. for about two hours and is then 



3: 



» » * 



ALCOA ALUMINUM and ITS ALLOYS 



« « « 



allowed to cool slowly in the furnace to a temperature of 500°F. 
The cooling rate should not exceed 50°F. per hour. 



SOLUTION HEAT-TREATMENT PRACTICE 



It should be stated at the outset that accurate temperature con- 
trol is necessary if proper results are to be obtained with strong 
aluminum alloys. The temperature limits for the solution heal 
treatment are rather close, and strict adherence to these limits 
is essential. Heating is, perhaps, most easily accomplished in a 
bath of fused sodium nitrate, heated with gas or oil so as to per- 
mit i -lose regulation of the temperature. Such a bath should be 
well stirred to avoid inequalities in temperature. This can be 
readily accomplished by alternately raising and lowering the 
load while it is being heated, making sure, however, that the 
metal is not raised above the surface of the bath. 

A furnace for heating in air can be used, provided it is so con- 

I ructed as to give uniform temperatures throughout, and to per- 
mit proper control. These results are more easily accomplished 
if provision is made for circulating the air. Both types of heating 
are in commercial use. The temperature range for the heat 
treatment of 17S, AITS, and BITS is from 930°F. to 950°F. For 
25S, 51S and 53S, the temperature should be 970°F., making 
certain that the temperature is at least 960°F. and not over 980°F. 
1 For 24S, the temperature range is 910°F. to 930°F. 

The time of heating depends upon the size of the load, the 
nature of the material, and the type of heating equipment. Jn a 
nitrate bath, a period of 25 minutes is usually sufficient; some- 
what shorter times have given satisfactory results. In the fur- 
naces in which air is the heating medium, the heating may re- 
quire several hours. It is essential that all of the metal in all parts 
of the furnace load be raised to the specified temperature. Heating 
periods longer than the minimum which will accomplish the re 

ults are not detrimental wilhin the limits that may be en- 

ountered in commercial fabricating practice. 

Alclad alloy products should be heated as rapidly as possibh 
and held for the minimum time which will insure that all of th< 
load has been brought up to the heat-treating temperature. If 
long heating periods are used, the alloying constituents of the base 



36 



ALUMINUM COMPANY of AMERICA « 



.,• 



metal will diffuse completely through the surface layer and the 
corrosion resistance of the product will be impaired. The thinner 
the material, the more essential it is that this precaution be ob- 
served. 

The metal is removed from the heating bath or furnace and 
quenched in water. The time interval between the removal of the 
metal and its quenching should be as short as possible, not more 
than a few seconds, if best results are to be obtained. 

The quenching medium should be cold water. If hoi water is 
used, the corrosion resistance of the alloy is decidedly inferior 
The effect of diffusion in Alclad products which have been heated 
too long is more harmful if they are not quenched in cold water. 
The volume of quenching water should be great enough that its 
temperature is not raised above 150°1 lo 1M> 1 by the heat of 
the load. When a nitrate heating bath has been used, it is neces- 
sary that any adhering nitrate be completely washed from the 
metal in order to avoid corrosion because of the tendency of the 
salt to take up moisture; it may be desirable to follow the cold 

water quench with a thorough washing in warm wat.-r because ol 
(he greater solubility and higher rate of solution of the salt at 
higher temperatures. The water should be warm, not h t, especial- 
ly if the alloy is to be formed before it has aged. 

The aging of ITS and 24S starts quite rapidly i mined mi . I, 
after quenching and proceeds at a gradually diminishing rat< 
until in about four days, at room temperature, it is practically 
complete. Severe forming of these alloys should be completed 
within one or two hours after quenching unless the rate of aging 
is retarded by storing them at low temperatures. II tored at the 
temperature of melting ice, immediately after quenching, good 
forming qualities may be retained for upwards of twenty-four 
hours, and at lower temperatures for even longer periods. 
On warming to room temperature, aging proceeds at the normal 

rate. 

PRECIPITATION HEAT-TREATMENT PRACTICE 

In order to develop the maximum strength in 25S, 51S and 53$, 

these alloys must be aged at an elevated temperature after they 
have been quenched. This operation, known as the precipitation 



3 



. 



ALCOA ALUMINUM and ITS ALLOYS 





The main concourse of a 

new railroad station is B 
striking example of t he use 
of aluminum in modern in- 
terior decoration. Doors, 
windows. Lighting fixtures, 

grilles, clocks, and trim are 
I ypical appointments in 

aluminum. 



This unusual memorial, 
made of alumilited alumi- 
num, is 35 feet high, SO feel 
long, and 20 feet wide. The 
wing spread of the largest 

gull is § l /i feel and that of 

the mallest is \ l /i feet- Du- 
rable, strong aluminum is 
being used more and iuoi 

in the field of slatuarv. 



38 



ALUMINUM COMPANY of AMERICA 



heat treatment, may be readily accomplished in an oven heated 
by means of steam coils and provided with a fan for air circula- 
tion. The temperature can be varied by changing the pressure in 
the steam coils. An electric furnace of proper design will also give 

satisfactory results. 

For 25S, it has been found that 290°F. gives satisfactory results, 
the temperature range being 285°F. to 295°F. The time will vary, 
with the nature of the material, from eight to fifteen hours. For 
51S and 53S, the preferred temperature limits are 310°F. to 320°F., 
and the aging time is eighteen hours. 

Some experimentation may be required to determine the best 
aging time for a given class of material. It should be remembered 
that aging for too long a time or at too high a temperature will 
lower the elongation and eventually the tensile strength as well. 
If the temperature is too low, much longer aging periods are re- 
quired to bring about the proper improvement of the allo\ 3. 

THEORY OF HEAT TREATMENT 

In the aluminum alloys which respond to heat treatment, the 
alloying constituents which give the increased strength and hard- 
ness are substances which are more soluble in solid aluminum at 
high temperatures than at low temperatures. 

The first step in heat treatment, frequently called the "'solu- 
tion heat treatment," consists in heating the alloy to a high 
temperature, below the melting point, to put as much as possible 
of the alloying constituent into solid solution, then quenching to 
retain this condition. When in solid solution, the alloying con- 
stituent is so finely dispersed that it is not visible with the micro- 
scope, even at high magnification. In effect, the alloying con- 
stituent has been dissolved in the aluminum and dispersed as 
completely as when sugar is dissolved in water. 

After quenching, the alloy undergoes an aging process which, 
if carried out at elevated temperatures, is railed a "precipitation 
heat treatment," because during this stage some of the alloying 
constituent which is held in solid solution precipitates from the 
solid solution in the form of extremely fine particles. This precip- 
itation may occur spontaneously at room temperature, as is tl 
case in the so-called "natural aging" of the alloys 17S and 24S, 



39 



» » » ALCOA ALUMINUM and ITS ALLOYS « « 



« 





or it may require a "precipitation heat treatment'* or "artificial 
aging" at about 300°F., as in the case of 25S, 51S or 53S. 

The particles of precipitated constituent may be so fine as to 
be invisible even under the most powerful microscopes, but their 
presence and effects are quite real, even though they cannot be 
seen. By continued heating they may, however, be caused to 
grow to sufficient size so that they become visible under micro- 
scopic examination. The size and distribution of the precipitated 
constituent are highly important in determining the mechanical and 
physical properties of the heat-treated alloy. There is an optimum 
condition which gives the best combination of properties, and a 
detailed knowledge of the heat-treatment process is necessary to 

pduce the best results with each alloy. 

The increase in hardness of the alloy as a result of heat treat- 
ment is pictured as being due to the "keying" action of the 
precipitated particles of the alloying constituent, which prevents 
slip along the crystal planes of the metal. To use a simple analogy, 
the action might be compared with the effect of ashes which pre- 
\ ent the feet of pedestrians from slipping on icy pavements. 

These changes with the corresponding increase in tensile proper- 
lies, tend to take place at ordinary room temperatures. In the 
case of ITS and 24S the age hardening is practically complete in 
about four days. 

The alloys 5 IS and 53S likewise show some increase in strength 
and hardness on standing at room temperatures after quenching, 
but after several days the rate of change becomes very slow. If, 
however, the temperature is raised, the rate of precipitation and 
particle growth is materially increased, with the result that much 
higher tensile and yield strengths and hardness can be developed 
in these alloys in a few hours than would be possible at room 
temperature over an indefinite period. Some of the forging alloys 
25S and 27S) show practically no change in properties on aging 
al room temperatures after quenching. At higher temperatures 
precipitation occurs with the consequent improvement in tensile 
properties. This second heating operation is called the "precipita- 
lion heat treatment". When the change occurs at ordinary tem- 
peratures, it is known as "aging". 



40 













CASTING ALLOYS 

Aluminum casting alloys may, like the wrought alloys, be 
classed in two groups: one, in which the improvement in proper- 
ties is accomplished by alloying alone; and two, the alloys in 
which heat-treatment processes are used to enhance further the 
mechanical properties. The casting alloys are given a number to 
designate the alloy composition; the heat-treatable alloy com- 
position numbers are followed by the letter "T" and a number to 
indicate the heat-treatment practice. Minor changes in the 
composition are indicated by a letter preceding the original alloy 
number. As in the case of the wrought alloys, the selection will 
depend upon the requirements of the particular application. 

Castings are almost invariably produced in the alloys of alu- 
minum except in a few cases where the electrical or other proper- 
ties of the pure metal are required. By the addition of various 
alloying elements or "hardeners" to aluminum, not only its tensile 
strength, but casting properties as well, are improved. By alloying 
alone, strengths almost double that of commercially pure alumi- 
num are obtained and the increase in strength is gained at a sacri- 
fice of most of the ductility of the parent metal. The elements com- 
monly used as hardeners are copper, silicon, magnesium, zinc, 
manganese, nickel and iron. The properties of the alloys vary de- 
pending upon the element or elements which are added and upon 
the percentages used. No two of the alloys in commercial use have 
identical properties, even though several of them may have sub- 
stantially identical tensile strengths. A brief discussion of the 



41 



» » y> 



ALCOA ALUMINUM and ITS ALLOYS 




Right — Alcoa Aluminum cylinder 
heads are cast in a metal mold to 
assure superior accuracy and sound- 
ness. 




Left — Lightweight com- 
bined with thermal effi- 
ciency makes aluminum 
the universal choice for 

pistons. 



Continuous improvements 
in mechanical properties 
of aluminum alloys, and 
advances in foundry and 
forging practice are con- 
tributing to engine per- 
formance and life. 



Left — Forged aircraft crankcase. 



Below — Sand cast aire raft cylinder 

head. 



42 



. » . ALUMINUM COMPANY of AMERICA « « « 

characteristic properties of the different alloys may be of value 
in addition to the tabulation of the mechanical properties irhich 

appear in Table 1 1. 

Aluminum alloy castings are poured not only in sand molds, 

bui in permanent metal molds; they are also die cast under pres- 
sure in die-casting machines. The type of casting process which is 

used will depend upon several factors I or large or for intricate 

eored castings, the use of sand molds is necessary. Because a 
metal mold or steel die is required, the use of die and perm nent 
mold eastings can be considered onl} where a sufficiently lai 
number of castings of the same pattern will he u-< d to justify the 
eost of the mold or die to the purchaser. The die-casting pr< n ess is 

particularly adapted to the quantity production of relatively 
small castings in which close dimensional tolerances are I mired 

and the eost of finishing must be held to a minimum. The di- 
mensional tolerances of permanenl mold i astingsare intermediate 
between those of sand castings and those of die castings and the 

surface (hush is comparable with that oldie castings. 

The mechanical properties of test bars casl in metal molds are, 

in general, higher than those from the same alloy east in sand. 
This same superiority in strength will be realized in commercial 
castings, except in so far as problems of mold design may partialh 
offset the advantages of the better metal structure. 

Sand Castings: The aluminum castings industry has developed 

from the use of an alloy called No. 12, containing about eight 
per cent of copper and such impurities as are present in nun- 
mercial aluminum ingot. Sand molds were first used, permanenl 
metal molds being a more recent introducl ion. The alloys 1 12 and 
212 have been developed from the original 12 alloy. The greater 
proportion of the castings produced in this country is still mad 
from these alloys, although the preponderance is not nearly as 

great as it was a few years ago. 

From the standpoint of the finished castings, there is little t< 

ehoose among alloys 12. 112, and 212. The mechanical proper- 



ties are substantially the same. All three contain approximate! 

Bill* 



eight per cent of copper; 212 differs from 12 in that small atten- 
tions of silicon and iron are made to control the ratio of th* 
elements and thereby improve the casting qualities of the alloy. 



! I 



» » » 



ALCOA ALUMINUM and ITS ALLOYS 



< 



Alloy 112 contains small additions of iron and zinc. For most uses, 
these small differences in composition are not significant. Alloy 
112 has somewhat superior machining qualities; however, except 
on large production jobs, this difference is probably not suf- 
ficient to determine the choice. For most applications, these al- 
loys may be used interchangeably and they are commonly speci- 
fied for general purpose castings. Where pressure tightness is re- 
quired, 109 alloy is sometimes used, although it is not suitable 
where it may be required to withstand shock. 

Alloy A-334 (U. S. Patent 1,572,489) has slightly better me- 
chanical properties than those of 12, 112, and 212 alloys, as well 
as somewhat superior casting properties. It can be used for the 
production of castings of intricate design, in which pressure tight- 
ness is required. It may be subjected to an artificial aging treat- 
ment to increase its hardness and to improve its machining quali- 
lies (U. S. Patent 1,394,534). 

Alloys containing silicon as the hardener have made a steady 
increase in commercial application since their introduction a few 
years ago, and today, these alloys represent a considerable per- 
centage of the foundry production both in this country and 
abroad. They have excellent casting qualities and can be used 
in the production of large thin section castings, which are intricate 
in design, or of castings which have adjoining heavy and light 
sections; they are also employed in the production of castings 
which must withstand fluid pressures without leaking. In addi- 
tion, the aluminum silicon alloys have excellent resistance to cor- 
rosion. Certain compositions are susceptible to heat treatment or 
to special foundry practices (modification) to improve their me- 
chanical properties. 

Alloy 43, containing five per cent of silicon, is most widely used 
in this country. Its tensile and yield strengths are somewhat 
lower than those of the aluminum-copper alloys (12, 112, 212), 
but it is appreciably more ductile and resistant to shock. Because 
of its excellent casting qualities and resistance to atmospheric at- 
tack, it is used practically to the exclusion of other alloys in the 
production of architectural and ornamental castings. Marine 
castings are also made of it because of it- satisfactory performance 
in salt-laden atmospheres. Alloy 45, containing ten per cent sili- 
con, has higher strength and hardness, but it is less ductile. It is 



44 



» » » 



ALUMINUM COMPANY of AMERICA « 



« « 



similar in other respects to 43 alloy, but not always quite so easily 
cast in leak-proof castings. Alloy 45 has been used in instrument 
frames and fittings because of its higher strength. 

Alloy 47 contains twelve and one-half per cent silicon. When 
cast without the use of special casting practices (such as those 
described in U. S. Patents 1,387,900, 1,410,461, 1,596,020, 1,572,- 
459, 1,570,893, 1,848,797, 1,848,798), the alloy is quite brittle and 
has a coarse crystalline fracture. By the use of the "modification" 
process, sand castings can be produced having distinctly higher 
strengths than those of 43 and 45 alloys, and higher elongation 
as well. The fracture of the "modified" or the chill cast alloy is 
fine-grained, and is commonly designated as "silky." 

Alloys containing magnesium in suitable proportions as the 
hardener, are even more resistant to corrosion than the aluminum- 
silicon alloys. Alloy 214, containing three and three-quarters per 
cent of magnesium, is used where service conditions require the 
maximum resistance to corrosive attack. It is more difficult to 
cast into intricate, leak-proof castings than the aluminum-silicon 
alloys, but has higher mechanical properties than 43 alloy and 
is distinctly more resistant to corrosion. It is employed in the 
production of castings for use in sewage disposal plants, chemical 
plants, and dairy equipment; it is also used in cast cooking uten- 
sils and for the production of aircraft and marine castings. Alloy 
216, containing approximately six per cent magnesium, has higher 
tensile and yield strengths but somewhat lower elongation. Be- 
cause of the higher magnesium content, special foundry technique 
is required for the production of satisfactory castings. Its resist- 
ance to corrosion is at least equal to that of 214 alloy. 

For certain special applications, other compositions may be 
recommended. Alloy 108 (U. S. Patent 1,572,489) contains both 
silicon and copper and combines some of the desirable character- 
istics of these two classes of alloys. Zinc is sometimes used as a 
hardener for aluminum; in fact the alloy most commonly used in 
f Europe contains zinc and copper as the alloying elements. For 

certain classes of castings, alloy 645 (U. S. Patent 1,352,271) is 
sometimes used; it is similar to the European type alloy, but con- 
tains iron as an essential constituent. Its mechanical properties 
are higher than those of the aluminum-copper or the aluminum- 
silicon alloys, but it is not advised for uses in which severe cor- 

45 



ALCOA ALUMINUM and ITS ALLOYS 



rosive conditions raav be encountered. It also should not be used 
where it will be subjected to elevated temperatures in service 
because it has lower strength under these conditions than do 
most of the other aluminum alloys. 



Permanent Mold Castings: Some of the alloys used in making 
sand castings are also poured into permanent molds, while others 
have been developed primarily for this purpose. The composition 
and physical properties of some of the more commonly-used per- 
manent mold alloys are listed in Table 12. Because of the finer 
grain structure resulting from the rapid solidification of the metal, 
permanent mold castings have greater susceptibility to heat 
treatment, and in the case of the aluminum-silicon alloys, the 
structure and mechanical properties are similar to those obtained 
by the modification processes in sand castings (U. S. Patent 
1,572.459). 

The great majority of pistons for internal combustion engines 
have been made from 122 alloy. More recently 132 alloy (U. S. 
Patent 1,799,837) has been developed to provide a material with 
a lower coefficient of thermal expansion than that of other com- 
mercial alloys of aluminum. The use of this latter alloy permits a 
closer fit of the piston in the cylinder. Pistons for certain of the 
aircraft engines are made from 142 alloy. All of these alloys are 
susceptible to heat treatment for improvement of their mechan- 
ical properties (I . S. Patents 1,394,534, 1,572,487, 1.572,488, 
1.508.556, 1,713,093, 1.822,877, 1.915.737, etc.). 

Alloys containing approximately eight per cent copper as th< 
principal alloying constituent, also find application in permanent 
mold castings. Although alloy 112 is used to some extent, varia- 
tions of this alloy, known as B113 and C113, have been developed 
particularly for this use. Controlled additions of silicon and zinc 
in these latter alloys provide the somewhat better casting char- 
acteristics desired for permanent mold use. 

Alloy A108, containing both copper and silicon, and combining 
some of the desirable characteristics of both classes of alloys, 
possesses good casting properties for the more intricate perma- 
nent mold castings. 

Alloys 138 and 144 provide excellent hardness in the cast condi- 
tion, which hardness is retained well at elevated temperature- 



46 



» » » ALUMINUM COMPANY of AMERICA « « « 

Alloy 138, particularly, has found applications for parts, such as 
flat-iron sole plates, where maximum hardness at operating tem- 
peratures is desired. 

Alloy A214 is a modification of the sand casting alloy 214, 
developed because of its superior qualities for casting in perma- 
nent molds. Its tarnish resistance is substantially the same as that 
of the sand casting alloy from which it was developed. 

The selection of an alloy for a permanent mold casting de- 
pends both upon the nature of the casting and upon the service 
it is to perform. This question can best be decided by consulta- 
tion with a representative of the Company, who is familiar with 
the production and the properties of permanent mold castings. 
Where this process is applicable, it offers not only the mechanical 
advantages which have been mentioned, but closer dimensional 
tolerances. Finishing costs may be materially lower than those 
for sand castings as a result of the saving in machining. 

neat-Treated Castings: The production of heat-treated cast- 
ings has increased over the past several years in response to the 
increasing demand for lightweight castings having mechanical 
properties superior to those of the common unheat-treated casting 

alloys. 

The alloy which has come into most general use is No. 195, con- 
taining four per cent copper. Solution heat treatment (T4) (U. S. 
Patent 1,572,487) causes a marked increase in the tensile and 
yield strengths and also higher elongations as compared with the 
alloy as cast. If the solution heat treatment is followed by a 
precipitation heat treatment (U. S. Patent 1,391.534), the tensile 
and yield strengths are increased and the elongation is decreased. 
The extent to which these changes occur vary with the time and 
temperature which are employed. Alloy 195-T6 has a higher 
tensile and yield strength, and an elongation about half that of 
195-T4. If, however, this latter alloy is allowed to age at room 
temperature for several months, properties nearly the same as 
those of 195-T6 are developed. Still higher tensile and yield 
strengths are obtained in alloy 195-T62, but the increase in these 
properties is obtained at the sacrifice of most of the elongation of 

the alloy. 

For use in permanent molds the heat-treated four per cent cop- 

47 



» » 



» ALCOA ALUMINUM and ITS ALLOYS « * « 




Above 

t ings, machined from forged blanks, 
simplify the use of AJcoa Alumi- 
num tubing for fuel and oil lines. 



quant its 

Ucoa Aluminum die castings offer 

i bin sections, smooth surfaces, close 
dimensional accuracy. 




Forged aluminum locomotive connecting rods and cast heat-treated cross-head 
assemblies reduce inertia and centrifugal forces and are durable in service. 



48 



» 



ALUMINUM COMPANY of AMERICA « « « 



i 



per alloy composition is modified by the addition of three per cent 
of silicon (U.S. Patents 1,508,556, 1,572,489). The symbol for des- | 

ignating this composition becomes B-195, and since it is regularly 
supplied in the solution heat-treated condition, castings are speci- 
fied as B-195-T4. A second modification known as D195 alloy, 
also supplied in the T4 condition, provides somewhat better 
mechanical properties than B195-T4, but, because of its less satis- 
factory casting characteristics, is limited to castings of relatively 
simple design. 

For very complicated castings which, if produced in the un- 
heat-treated alloys, would require the use of one of the aluminum- 
silicon alloys for successful or economical manufacture, a new high 
strength alloy has been developed. This alloy, 356 (U. S. Patents 
1,472,739, 1,508,556, etc.) contains silicon and magnesium as 
hardening agents and, like 195, responds to heat-treatment proc- 
esses. It is recommended for the production of castings in which 
superior mechanical properties are desired, but which would be 
difficult or uneconomical to manufacture in 195 alloy because of 
foundry limitations. 

Like 195 alloy, 356 alloy is produced in several heat treatments, 
the most common of which are 356-T4, and 356-T6, the properties 
varying in the same manner as in the case of the former alloy. 
The mechanical properties are slightly lower than those of 195 
as determined from standard test bars. A complicated casting 
made in this alloy may, however, be stronger than if it were 
made in 195, because of the avoidance of casting defects which 
could not be avoided in producing it from the latter alloy. For 
ordinary work, however, 195 alloy is usually recommended be- 
cause of its long record of satisfactory performance and its greater 
ruggedness in withstanding shock or suddenly-applied load. 

Alloy 355 (U. S. Patents 1,508,556, 1,848,816, etc.) containing 
slightly more copper and less silicon, also has excellent casting 
qualities, and, in addition, retains its strength well at tempera- 
tures up to 400°F. Like the other alloys in this group, it is sus- 
ceptible to a variety of heat treatments to develop different 
properties. It is used in the manufacture of water-cooled cylinder 
heads for motors and for other complicated castings where its 
leak-proof properties and heat-resisting qualities are of im- 
portance. In case higher temperatures are to be withstood, the 



49 



ALCOA ALUMINUM and ITS ALLOYS 



modification of the alloy A355 (U. S. Patents 1,595,058, 1,848,- 

816, etc.) is recommended. 

Both 355 and 356 alloys are susceptible to improvement in 



tensile strength and hardness, at some sacrifice in ductility, 
through an aging treatment alone. These treatments are of par- 
ticular advantage for large and intricate castings whose design 
does not permit the standard quenching treatment without the 
introduction of undesirable quenching stresses. Aging treatments 
are also desirable for castings used at elevated temperatures and 
for controlling the "growth" in castings where this factor must be 
considered. 

Alloy 220-T4 has the highest combination of tensile and yield 
strengths, elongation and impact resistance of any of the alu- 
minum casting alloys. This alloy contains ten per cent magnesium, 
and for this reason, requires special foundry technique (covered by 
several U. S. Patents) to avoid oxidation of the magnesium from 
the surface of the metal with the consequent darkening of the 
casting and loss in mechanical properties. Alloy 220-T4 possesses 
exceptional machining characteristics and finds application for 
certain sand castings in which free cutting characteristics are 

desired. 

The choice of an alloy for any particular application may usual- 
ly be made from the physical properties and the general char- 
acteristics of the various alloys which have been discussed. The 
sen ices of the technical staff of this Company are also available, 
on request, to assist in the selection of the alloy which is best 
suited for any requirement. 



Die Castings: Die castings of aluminum alloys have the ad- 
\antages of lightness, corrosion resistance and permanence of 
dimensions as compared with some of the other metals which are 
used in the die-casting process. Several alloys are cast in this 
manner, those which are recommended by this Company being 
shown in Table 18, together with their approximate compositions 
and mechanical properties. 

In the case of die castings, the choice of alloy is determined 
in some measure by the nature of the casting. The different alloys 
have different casting characteristics, and the ability to produce 
the most satisfactory casting of the given design may often be 



50 



ALUMINUM COMPANY of AMERICA 



the deciding factor in the selection of the alloy, rather than the 
mechanical properties as determined from a test specimen. The 
die-casting specialist should be consulted both as to the possibili- 
ties of this product and the selection of the alloy. 

Die castings offer the maximum advantages from the stand- 
point of low finishing costs because of their accuracy of dimensions 
and good surface. Savings also result because of the ability to 
cast thinner sections than are possible by other methods. 



DESIGN OF ALUMINUM ALLOY CASTINGS 

The mechanical properties of the various alloys referred to in the 
foregoing section and contained in the tables of the Appendix, are 
values obtained from standard A.S.T.M. H" diameter test speci- 
mens separately cast and tested without machining the gauge sec- 
tion. These test specimens are cast under conditions which du- 
plicate as closely as possible the conditions of solidification of the 
casting. When cast under such standard conditions, these test 
specimens serve as a control of the metal quality, and in the case 
of heat-treated alloys, they also serve as a control of the heat- 
treating process, since they must be heat treated with the cast- 
ings they represent. 

The properties of separately cast test specimens do not neces- 
sarily represent the properties of commercial castings, and may 
be either higher or lower depending on a number of factors which 
influence the rate of solidification of the metal from the molten 
state. For the same reasons, the properties of test specimens ma- 
chined from castings will vary depending on the location from 
which they are taken. Such foundry considerations as section 
thickness, gating and risering, chilling, pouring temperature, 
permeability and moisture content of sand, and any other factors 
which influence the rate of metal solidification, have a material 
effect on the mechanical properties. 

These relations are not peculiar to aluminum alloy castings 
but exist in castings of all metals. They introduce two specific 
problems for the designer of cast metal parts; first, the selection 
of the proper alloy for such parts considering such factors as 
foundry characteristics and physical properties; and second, the 
selection of the proper factor to apply to the properties specified 



51 



» » » 



ALCOA ALUMINUM and ITS ALLOYS « « « 



for an alloy in determining the design stress. Such factors must 
take into account the type of service in which a casting will be 
used as well as the variation in the properties of the sections of 
each commercial casting. There is no known "rule of thumb" 
from which these factors can be determined, and in fact most de- 
signers develop their particular method from experience with 
specific metals and types of castings. The properties of test speci- 
mens machined from the specific casting being designed and 
proof load or breakdown tests on the casting assuming service 
loading conditions, provide data which are extremely useful in this 
connection if either the design or application of the casting is 
new. The latter method, particularly, is finding favor as a means 
of checking the design of aluminum alloy castings. 

The services of the engineering and technical staffs of this 
Company are available on request to assist in the selection of al- 
loys for casting applications as well as the designing of cast parts. 



MECHANICAL PROPERTIES OF ALUMINUM ALLOYS 

AT HIGH AND LOW TEMPERATURES 

In common with other materials, the tensile strength, yield 
strength and modulus of elasticity of aluminum alloys are lower 
at elevated temperatures than they are at ordinary temperatures. 
The elongation increases as the temperature is raised until at a 
temperature a little below the melting point it drops nearly to 
zero. This corresponds to the "hot short" range of the metal. 

Factors to apply to the mechanical properties at ordinary 
temperatures, when designing for high temperature service, are 
shown in Table 7. 

Tests made at a temper of -114°F. have shown that both the 
tensile strength and elongation are higher than at ordinary 
temperatures. 



52 















APPENDIX 



APPENDIX 



INTRODUCTION 



In the Appendix will be found tables showing the phys- 
ical properties, compositions, typical mechanical properties, 
guaranteed minimum mechanical properties, dimension 
tolerances and available commercial sizes of the various 
aluminum alloys and aluminum alloy products. Attention 
is called to the fact that the typical properties of the alloys 
represent approximate average values for use in comparison 
with similar values commonly given for other materials and, 
obviously, cannot be used in purchase specifications for the 
various alloy products. The available alloys and the limiting 
sizes shown for the different commodities represent normal 
commercial practice. It may be possible in some cases to ex- 
ceed those limits or to produce the commodity in other 
alloys. Inquiries for such special material should be taken up 
with the nearest sales office of the Company (See page 92). 
In a general discussion of aluminum and its alloys, it is not 
possible to anticipate nor to discuss adequately all questions 
which may arise in connection with the selection and use of 
aluminum alloys. Other booklets covering subjects such as: 

Machining Aluminum and Its Alloys 
The Riveting of Aluminum 
The Welding of Aluminum 

also booklets and other literature dealing with the use of 
aluminum in specific fields, such as the Dairy, Brewing, 
Power (Bus Bar and Cable Conductors) Chemical, and Food 
processing and packaging industries, may be obtained on 
application to the nearest sales office of the Company (See 
page 92). 

Moreover, the advice and assistance of the sales repre- 
sentatives and through them of the Technical and Engi- 
neering Staffs of the Company are available to users or 
prospective users of aluminum products. 



54 



\PPENIMX 



TABLE I rANDARD COM \1<>l>mi 

\\ ROl GUI VLL( rt S 

(i '.ornriHHliiir marked ' ar< tandard 



MI..V 


!,■ .-1 


Plata 


Win 


Rod 
i* ii« 1 
Bar 


Rolled 


1 1 

traded 
Shapes 


1 ubing 
and 


2S 

ss 

is 


* 
* 


* 


* 
* 


* 

* 




* 
* 


* 


i |S 

I7S 


■ 


► 


* 


i 

* 


* 


1 


♦ 


a lad I7S 


* 






• 








A I S S 
















185 




* 


■ 








24S 


* 














\|,I;mI MS 


* 
















* 




















■ 










92S 

ns 


* 


* 




» 




# 


H 


A :. 1 S 






■ 










• »S 

. is 


* 

* 


• 
* 


* 
* 


* 
* 






1 
1 


70S 






■ 











Ml 






* 






* 



* 

* 









•Commodities marked >< M p**"** "' « ( v 

duction. Salee repreaentati »f Al ;-";;;'" 

consulted concerning the possibilit> -l obi n»in« «.m*r 
van-- us alloys. For list of sales offi " 



. I'S 



i?e •» 






5 



ALCOA ALUMINUM and ITS ALLOYS 



« 



Alloy 



2S 
3S 

4S 

14S 

ITS 

A17S 

B17S 

18S 

24S 

25; S 

27S 

32S 

5lS 

A51S 

52S 
5SS 

7ns 



TABLE 2— NOMINAL COMPOSITION OF 
WROUGHT ALUMINUM ALLOYS# 



Per Cent of Alloying Elements. Aluminum and Normal Impurities 

Constitute Remainder 



Copper 



4.4 
4.0 
2.5 
3.5 
4.0 
4.2 
4.5 
4.5 



1.0 



Silicon 



0.8 



0.8 
0.8 
12. 
1.0 
1.0 



0.7 



Man- 
ganese 



1.25 
1.25 
0.75 
0.5 



0.5 

0.8 
0.8 



o 7 



Mag- 
nesium 



1.0 

0.35 

0.5 

3 

0.3 

0.5 

1.5 



1. 

0.6 
0.6 
2.5 

1 . 25 
0.4 



Zinc 



10 



Nickel 







2.0 



i * 



* • 



0.8 



, 



- . 



• • 



Chro- 
mium 



o 







25 
25 

25 



Tin 







05 



TABLE 3 -APPROXIMATE COMPOSITION! OF ALUMINUM 

SAND CASTING VLLOYSjJ 



\ ll< 



12 

43 

47 

108 

1 9 
112 

1** 

14-2 
1 05 
212 

214 
216 
220 
A 334 
9 5 5 

A 3 55 
356 
64.3 



JVr Cent (if Alloying Elements. Aluminum and Normal Impurities 

Constitute Remainder 



oppei 



8.0 

• • • . 

• 

4.0 
12.0 

7 5 
10 ft 

4.0 

4.0 

8.0 



• • 



• • 





1 25 
14 

2 5 



Iron 



1.2 
1 



1 







1 . 6 



Silicon 



5.0 

12.5 

i.O 



1 .2 



4.0 
5.0 

5.0 

7.0 



• • 



Zinc 



• • 



1.5 



11.0 



Mag- 
nesium 



• • 



0.2 
1.5 



3.75 
6 

10.0 

0.3 

o.a 

0.5 
0.3 



Nickel 



2 











75 



Man 
ganetM* 










75 



• • 



M*at- treatment symbols have been omitted sin- om position does not \ar 
r different heat-treatment practices. #The compositions and /or beat 

treatment of many of these alloys are patented. 



56 



» , » ALUMINUM COMPANY of AMERICA « 



«; 






«c 



TABLE 4— PRO 


iPERTlES Oh \ 


VKUUUJiT AL 


LUIS 


Wrought 
Alloys 


Specific 
Gravity 


Weight 

Lbs. per 

Cu. In. 


Electrical 

Conductivity 

Per Cent of 

International 

Copper Standard 


Thermal 
Conductivity 

at 100°C 
C.G.S. Units 


2S-0 

2S-H 


2.71 
2.71 


0.098 
0.098 


59 
57 


.53 
.51 


3S-0 
3S-^H 

3S-HH 
3S-H 


2.73 
2.73 
2.73 
2.73 


0.099 
0.099 
0.099 
0.099 


50 
42 
41 

40 


.45 
.38 
.37 
.36 


4S-0 

4S-HH 
4S-H 


2.72 

2.72 
2.72 


0.098 
0.098 
0.098 


40 
40 
45 


.36 
.36 
.40 


14S-0 

1 4S-T 


2.80 
2.80 


0.101 
0.101 


50 
35 


.45 
.32 


17S-0 
17S-T 


2.79 
2.79 


0.101 
0.101 


45 

30 


.40 

.27 


18S-0 

18S-T 


2.80 
2.80 


0.101 
0.101 


45 
35 


.40 

.32 


24S-0 

24S-T 


2.77 
2.77 


0.100 
0.100 


50 
30 


.45 

.27 


25S-0 

25S-W 

25S-T 


2.79 
2.79 
2.79 


0.101 
0.101 
0.101 


50 
35 
35 


.45 
.32 
.32 


27S-0 
27S-W 

27S-T 


2.80 
2.80 
2.80 


0.101 
0.101 
0.101 


50 
35 

40 


.45 
.32 
.36 


32S-0 
32S-T 

51S-0 

51S-W 

51S-T 


2.66 
2.66 
2.69 
2.69 
2.69 


0.096 
0.096 
0.097 
0.097 
0.097 


40 
35 
55 
45 
45 


.36 
.32 
.50 
.40 
.40 


A51S-0 

A51S-W 

A51S-T 

52S-0 

52S-H 


2.69 
2.69 
2.69 
2.67 
2.67 


0.097 
0.097 
0.097 
. 096 
0.096 


50 
40 
40 
35 
35 


.45 
.36 
.36 
.32 
.32 


53S-0 

53S-W 

5SS-T 
70S-O 
70S-T 


2.69 
2.69 
2.69 
2.91 
2.91 


0.097 
0.097 
0.097 
0.105 
0.105 


45 
40 
40 
40 
35 


.40 
.36 
.36 
.36 
.32 



57 



» 



» » 



ALCOA ALUMINUM and ITS ALLOYS « « 



« 



TABLE 5— APPROXIMATE RADII FOR 90° COLD BEND 
OF ALUMINUM AND ALUMINUM ALLOY SHEET 

Minimum permissible radius* varies with nature of forming operation, type of 
forming equipment, and design and condition of tools. Minimum working 
radius for given material or hardest alloy and temper for a given radius can be 
ascertained only by actual trial under contemplated conditions of fabrication. 



Alloy and 
Temper 




2S-1.H 

2S-MH 
2S-H 

3S-0 

3S-I4H 

SS-^H 
SS-H 

4S-0 

i>- dl 

4S- ,11 

l?S-(.) ; 
17S-1 ») 

17S-R1 ') 



Bend 

Classification** 



A 

B 
h 
D 
F 

A 
B 
C 
I! 
(. 

R 
D 

I 

II 

J 

B 

II 
J 



Alloy and 

Temper 



A17S-0 
A17S-T 

B17S-0 
B17S-T 

24S-OC 1 ) 

24S-RTC 

51S-0 
51S-W 

5 1 S-T 
52S-0 

52S-UH 

,v2S-' 2 n 

52S-H 
53S-0 

5,'iS-W 

5SS-T 



Bend 
Classification** 



B 
F 

B 
G 

B 
J 
K 

A 

I 
K 

A 

G 
D 

F 

G 

A 

F 
(. 



*See page 24. 
**Foi • orresponding bend radii see following table: 



BUM! 


HFQUIBFD FOR M>< 


BEAD FN TERMS OF THICKNESS, t 








Approximate 


Thick n<i«S 






bSGati| 


26 


20 


14 


8 


5 




Inch 


016 


032 


064 


128 


0.189 


0.258 


Inch 


14 


% 


! 


% 


% 


. 


= ^ 




















= B 











; 


0-1 1 


0-lt 


* 











0-11 


0-lt 


] 2t-ljvl 


■± D 








0-11 


\i\r-1i4\ 


lt-2t 


1 Htr-St 


S !- 


0-1 1 


It 


1 2 t-i ! £t 


It-it 


1 y 2 t-st 


2t-4t 


5 F 


0-11 


'-t-l 1 ^ 


lt-2t 


1 \ £t-St 


21-4 1 


2t-4t 


U <. 


•vt-l'.t 


It- 21 


1 ! £t-si 


2t-4t 


3t-at 


41 6t 




n-/\ 


1 ! vt-31 


2t-4l 


3t-.it 


4t-0t 


4t-0l 


J 


1 ' vt-3l 


fct-4t 


3t-5t 


4t-(it 


4l-0t 


51-71 


- K 


2t-4t 


3t-,5t 


3t-5t 


4t-0t 


5t-7t 


01- 101 



I 



I'J 






U< lad 17S and \1< Ind £4S can be bent oxer slight! > smaller radii than the 
crespooding tempera of the un coated alloy. 

Immediately after quenching, tie -■ all* can Deformed ovei appreciably 

•-uinller radii. 



V 






» 



» 



ALUMINUM COMPANY of AMERICA * 



« 



« 



TABLE 6— AVEF 


AGE COEFF1C1E 


JN 1 OF IHHttMA 


l. nArAi^aiu.^ 




PER DEGREE FAHRENHEIT 








Temperature Range 




Alloy 


1 








68-212 °F. i 


68-392 °F. 


68-572 °F. 


2S1 








3S \ 


0.0000133 


0.0000138 


0.0000144 


4Sj 








14S1 








17S 

1 18S 


§ 


0.0000122 


0.0000130 


0.0000138 


25S 








27S 










32S 


0.0000108 


0.0000114 


0.0000119 


5lS 


0.0000130 


0.0000136 


0.0000141 


70S 


0.0000136 


0.0000144 


0.0000150 


12 


0.0000125 


0.0000130 


0.0000136 


43 


0.0000122 


0.0000127 


0.0000133 


47 


0.0000111 


0.0000113 


0.0000119 


108 ' 










109 


\ 


0.0000122 


0.0000127 


0.0000133 


112 










113 


- 








122 


0.0000122 


0.0000127 


0.0000130 


132 


. 0000105 


0.0000111 


0.0000116 


142 


0.0000125 


0.0000130 


0.0000136 


144 


0.0000119 


0.0000125 


0.0000127 


195 


0.0000127 


0.0000133 


0.0000138 


15195 


0.0000122 


0.0000127 


0.0000133 


D195 


0.0000127 


0.0000133 


0.0000138 


.J ^ Jl **" *-"* 

212 


0.0000122 


0.0000127 


0.0000133 


214\ 
21G J 
220 


0.0000133 


0.0000138 


0.0000144 


0.0000136 


0.0000141 


0.0000147 


A334 \ 
355 J 
A355 


0.0000122 


0.0000127 


0.0000133 


0.0000119 


0.0000125 


0.0000130 


i m. UP *-^ *P* 

356 


0.0000119 


0.0000127 


0.0000130 


Brass 


0.0000107 






Cast Iron 


0.0000059 






1 Copper 


0.0000093 






! Lead 


0.0000150 






Monel 


0.0000078 






Nickel 


0.0000057 






Steel 


0.0000061 






I Zinc 


0.0000165 










59 



» 



» 



» 



ALCOA ALUMINUM and ITS ALLOYS 



« 



« 



« 





TABLE 7— FACTORS FOR DESIGN STRESSES 








AT ELEVATED TEMPERATURES 




Alloy 


100°F. 


200°F. 


300°F. 


400°F. 


500°F. 




3S-0 

3S-KH 

3S-H 


1.0 
1.0 

1.0 


0.85 
0.75 
. 75 


0.70 

1 0.60 

0.60 


0.60 
0.45 

. 35 


0.40 
0.30 
0.25 




4S-0 

4S-MH 
4S-H 


1.0 
1.0 
10 


0.90 
0.90 

1 . 80 


0.80 
0.65 
0.55 


0.50 
30 
0.25 


0.40 
. 25 
0.20 


- 


1 1 7S-T 
A 1 7S-T 


10 
10 


0.90 
0.90 


0.60 
0.60 


0.30 
0.30 


0.15 
0.15 


WROUG 


24S-T 
25S-W 

25S-T 


1.0 
1.0 
1.0 


0.85 
1.00 
0.90 


0.70 
75 
0.60 


0.40 
0.30 
0.25 


0.20 
0.15 
0.10 




51S-W 

51S-T 


10 

1.0 


1.00 

75 


0.80 
0.55 


0.30 
0.20 


1 5 
0.10 




52S-0 

52S-» 4 H 


1.0 

i.O 


. 95 
95 


. 90 
80 


. 70 
. 50 


0.55 
. 30 




58S-0 

53S-T 


1 
1 


. 80 
85 


60 
0.70 


50 
0.40 


0.30 
0.15 




12 

43 


10 
1.0 


1.00 
0.80 


0.90 
0.70 


0.75 
0.55 


0.60 
0.40 




112 

122-T2 
122-T61 


1.0 
1.0 
1.0 


1.00 
90 
90 


0.90 
0.80 
0.80 


0.75 
0.70 
0.50 


0.60 
. 60 
0.20 




142-T <>1 


1 
10 


1 . 00 
. 90 


90 
80 


0.85 
0.65 


30 
35 


CVSI 


195-14 


1.0 


95 


0.85 


0.45 


. 30 


214 

220-T4 


1 

1 


0.95 
0.85 


0.85 
0.70 


0.70 
0.50 


0.50 
0.30 




355-T4 

355-T6 
S55-T51 


1 

1 
1.0 


1 .00 

0.95 
0.90 


0.90 
0.85 
80 


0.50 
0.65 
0.50 


20 
0.25 
0.20 




A355-T5J 

AS55-T59 

S56-T4 


10 
1 
I 


. 95 
90 
95 


0.90 
0.80 
0.85 


. 30 
0.70 

0.50 


0. 15 

40 

o 






» 



ALUMINUM COMPANY of AMERICA 



« « 



FABLE 8— CONVERSION FACTORS 



Weight of 



5lS 

1?S or 25S 

24S 

2S 

2S 
2S 

2S 



Multiplied 

By 



2.92 
2 . 82 
2.83 
2.89 

3.1 
3.3 

3.26 



Gives Weight 

of Equal 

Volume of 



Steel 
Steel 
Steel 
Steel 

Brass 
Copper or Monel 

Nickel 



Weight of 



2S 

2S 
2S 
2S 

2S 
2S 

2S 
2S 



Multiplied 
By 



2.7 
2.62 
1.01 
1.005 

1.03 
1.02 
0.985 
0.99 



Gives Weight 

of Equal 

Volume of 



Tin 
Zinc 
3S 
4S 



17S or 25b 
24S 
52S 
5lSor53S 



Alloy 



17S 
A17S 
B17S 

24S 

25S 

51S 

53S 



TABLE 9— CONDITIONS FOR HEAT TREAT 

OF ALUMINUM ALLOYS 

(All Temperatures in Degrees Fahrenheit) 



Solution Heat Treatment 



Temper- 
ature 



Approxi- 
mate 
Time of 
Heating 



Quench( 2 ) 



930-950 
930-950 
930-950 

910-930 
960-980 

960-980 
960-980 



0) 
C 1 ) 
0) 

0) 

0) 



Cold water 
Cold water 
Cold water 

Cold water 
Cold water 

Cold water 
Cold water 



Temper 

Desig- 
nation 



Precipitation Heat Treatment^) 



Temper 
ature 



Time of 
Aging 



25SW 

51SW 

53SW 



Room 
Room 
Room 

Room 
285-295 

315-325 



4 days( 8 ) 
4 days( 3 ) 
4 days( 3 ) 

4 days( 3 ) 
12 hours 

18 hours 



Temper 
Desig- 
nation 



315-325 18 hours 



17S-T 
A17S-T 
B17S-T 

24S-T 
25S-T 

5 1ST 
53S-T 



(0 In a molten nitrate bath, the time varies from 10 to 60 minutes depending 
upon the size of the load and the thickness of the material. In an air fur- 
nace, proper allowance must be made for a slower rate of bringing the load 
up to temperature. For heavy material such as bar and forgings a longer 
time at temperature may be necessary. 

(2) It is essential that the quench be made with a minimum time loss in transfer 
from the furnace. , 

(3) More than 90 per cent of the maximum properties are obtained during the 

first day of aging. 

( 4 ) Precipitation heat treatment at elevated temperatures is patented. 



61 



» » 



» 



ALCOA ALUMINUM and ITS ALLOYS 



« 



« 



« 



TABLE 10— TYPICAL* MECHANICAL PROPERTIES OF 

WROUGHT ALUMINUM ALLOYS0) 



Alloy 

and 

Temper 



2S-0 

2S-KH 
2S-MH 
2S-H 

3S-0 
3S-MH 

ss-y 2 u 

3S-^H 
i>-H 

4S-0 
4S-^ 4 II 

48- ^H 
4S-H 

17S-0 

17S-T 

17S-RT 

Uclad L7S-T 

\Uhu\ its-KT 

A17S-0 

A17S-T 

B17S-0 

Bl?s T 

24S4 ) 
24S-T 

24S-RT 

Aklad MS-T 
Uclad 24S-HT 

25S-0 

25S-W 

MS-T 

5 1 S-0 

51S-W 
5 1 S-T 



TENSION 



Yield 

Strength^) 

(Set = 

0.2%) 

Lbs. per 

Sq. In. 



4 
13 
14 
17 
21 

5 
15 

18 
21 
25 

10 
25 
31 
35 
38 

L0 
S 5 

32 

40 

8 

24 

B 
£5 

10 

43 

40 

49 

10 

25 
35 

5 1 1 

C 
20 

38 



000 
000 
000 
000 
000 

000 
000 
000 
000 
000 

000 

000 

000 
000 

000 

000 

000 

000 

000 
000 

000 
000 

000 
000 

000 

000 
000 

000 
000 



000 

000 
000 



Ultimate 
Strength 

Lbs. per 
Sq. In. 



13 
15 

1? 
20 
24 

1G 
18 
21 
25 
29 

20 
31 
35 
89 

42 

20 
58 
01 

5? 

22 

43 

22 

48 

20 
05 
08 

62 



000 20 

000 48 

000 ; 58 

000 00 



10 

35 
48 



000 
000 
000 
000 
000 

000 

000 

000 

000 
000 

000 

000 

000 
000 

000 
000 

ooo 

000 
000 

000 

000 
000 

000 
000 

000 
000 
000 

000 

000 

00 

00 (J 

000 

000 

000 
000 
000 



Elongation ( 3 ) 
Per Cent in 2 In 



c 



'_ 



«•- — •- 

- ■£., 
C. 

f. 



v: 






Z a Jr 

Sirs - 
5 E 



35 

12 

9 

6 

5 

30 

10 

8 

5 

4 

20 
6 
5 
3 

3 

20 
£0 

13 

18 
11 

24 
24 

22 
22 

20 
20 
13 

18 
11 

20 
1H 

20 
30 

24 

14 






0. LQ 



ffl 



ev 



45 

25 

20 
17 
15 

40 
20 
10 
14 
10 

25 

15 

10 

7 

5 

22 
22 



27 
27 

23 
23 

22 
22 



HARD- 
NESS 



Brinell 

500 kg. 

10 mm. 

Ball 



23 
28 
32 
38 
44 

28 
35 
40 
47 
55 

45 
5', 

05 
73 
80 

45 
100 
110 



• • 

38 
70 

38 

80 

42 
105 
116 



SHEAR 



Shearing 

Strength^) 

Lbs. per 

Sq. In. 



* 


- 


22 


\r> 


22 


80 


22 


100 


11 


115 


35 


28 


30 


04 


10 


95 



9,500 
10,000 
11,000 
12,000 
13,000 

11,000 
1 2 , 000 
14,000 
15,000 
10,000 

16,000 
17,000 
1 9 , 000 
21,000 
23,000 

18,000 
35,000 
36 , 000 

32,000 
32 , 000 

15,000 
25 , 000 

15,000 
29,000 

18,000 
40,000 
41,000 

39,000 
39,000 

18,000 
30,000 

35,000 
37,000 
1 1 , 000 

2 i . oo 

30 , 000 



FA- 
TIGUE 



Endurance 

Limit( s ) 

Lbs. per 

Sq. In. 



5,000 

6,000 
7,000 
8,000 
8,500 

7,000 
8,000 
9,000 
9,500 
10,000 

14,000 
14,500 
15,000 
15,500 
16,000 

11,000 

15,000 



13,500 



• ••••• 

15,000 

1 4 , 000 
14,500 






9 , 000 
14,500 
15,000 

13,000 

. 500 
10,500 
J 0,500 



62 



» 



» 



ALUMINUM COMPANY of AMERICA « 



« 



« 



TABLE 10-TYPICAL* MECHANICAL PROPERTIES 
WROUGHT ALUMINUM ALLO\ S( 1 )— Continued 



TENSION 



Alloy 

and 

Temper 



Yield 
Strength^) 
(Set = 
0.2%) 
Lbs. per 
Sq. In. 



Ultimate 

Strength 

Lbs. per 

Sq. In. 



Elongation( s ) 
Per Cent in 2 In. 



HARD- 
NESS 



SI I K A H 



52S-0 

52S-KH 
52S-HH 

.-.■es-%H 

52S-H 

53S-0 

53S-W 

53S-T 



14,000 
26 , 000 
29 , 000 
34,000 
36,000 

7,000 
20,000 
32 , 000 



29 , 000 
34,000 
37,000 

39 , 000 
41,000 

16,000 
33 , 000 
38,000 



— K A 



25 
12 

10 
8 

7 

25 

22 
14 



r = *- 

lis I 
gig J 



FA- 
TIGUE 



Hrinell 

500 kg. 

10 mm 

Ball 



Shearing 
Strength( 4 
Lbs. per 
Sq. In. 



) 



30 

18 

14 

10 

8 

35 
30 
20 



45 

62 
67 
71 
85 

26 
65 

80 



18,000 
20 , 000 
21,000 
23,000 
24,000 

11,000 
22,000 
26,000 



Endurance 

Limit( 5 ) 

Lbs. per 

Sq. In. 



17,000 
18,000 
19,000 
20,000 
20,500 

7,500 
10,000 
11,000 



*For guaranteed minimum values, see Tables 13 to 17. 

(i) Young's modulus of elasticity is approximately 10,300,000 pounds per 
square inch, 

m Stress which produces a permanent set of 0.2 per cent of the initial gauge 
( } S (American Societ? for Testing Materials Specification for Methods 
of Tension Testing, E 8-33.) 

(*) Elongation values vary with the form and size of ^on test specmen 
Thin sheet has somewhat lower elongation than values for Vfo ; inch sheet 
shown in table. Thicker material, from which standard round tension test 
specimens (0.505 inch diameter) are tested, may have lower elongation 
because of the effect of commercial flattening operations on this property. 

(4) Single-shear strength values obtained from double-shear tests. 

(5) Based on withstanding 500,000,000 cycles of completely reversed stress, 
using the R. R. Moore type of machine and specimen. 



63 



x> 



» 



ALCOA ALUMINUM and ITS ALLOYS 



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65 



* * 



> ALCOA ALUMINUM and ITS ALLOYS « 



i 



TABLE 12 



A LLO Y 



43 

Aios 

112 

B113 
C113 

122 
12 

1 2 2 
1-2-2 



T52 
T6.5 
T551 
T552 



U32-T4 
V.182 T551 



IMS 

1 4 2 
142 
142 



T61 
T571 



1 14 
144-T4 



Bl»5 

Kl!J> 

I ) 1 9 5 



T62 
T4 



\214 
555-T4 



PROPERTIES^) OF ALUMINUM PERMANENT 

MOLD ALLOYS(3) 



Approximate Composition — 
Per Cent of Alloying Elements; 
Aluminum and Normal Impurities 
Constitute Remainder 



- 

- 






# ■ 



■ • 



4. 5 
7..") 1.2 

7.5 1.2 



r. 



- 
s 



E 

5 



7.5 

10.0 
10.0 

10.0 

10.0 

0.8 



1.2 

1.2 
1.2 
1.2 

O.s 



5.0 

1.5 



■ • 



1.5 

4.0 



0.8 0.8 



10.0 

1.0 

4.0 

4.0 

10.0 
10.0 

1.5 

4.5 

5.5 



1.2 



1.2 

1.2 



12.0 
12.0 



4.0 



4.0 
4.0 

2.8 

2.8 

0.7 



1.5 



5 . 

.;.0 



a 

X 



• ■ 



* 



* ■ 



* ■ 



* • • 



0.2 
0.2 
. 2 
0.2 

1.0 
1.0 

0.2 
1.2 
1.2 
1.2 

0.2 
0.2 



2.0 



■ • 



3.7.3 
0.5 






• • 



• • 



2.5 
2.5 



2.0 
2.0 
2.0 



* • 



Mini- 
mum 
Ultimate 
Strength 
Pounds 

per 

Square 

1 nch 



21,000 

24,000 
23,000 

24,000 
24,000 

27.000 
38,000 
30,000 
27,000 

30,000 
30,000 

20,000 
26,000 
40,000 
33,000 

20,000 
36,000 

33,000 
42,000 
35,000 

21,000 
31,000 
30,000 



Mini- 
mum 
Elonga- 
tion 
Per Cent 
in 2 
Inches 



2.5 



• • 



* 



- * 



* • 



1.0 



4.5 

1.0 
7 . 

2.5 

4.5 
1.5 



BrinelK 2 ) 
Hardness 



45-55 

65-80 
70-90 

70-90 

70-00 

9.5-12 

125-150 
125-150 
1 00- 1 2 

90-120 
85-115 



85 

00 

100 

90 

85 
100 



110 
115 
130 
120 

lio 

130 



70-90 

00-110 

00-80 

50-Ci 
70-85 
85-100 



Typical 
Dens- 
ity 

Pounds 

per 
Cubic 
I nch 



0.097 
0.100 
0.104 

0.103 
0.103 

0.104 
0.104 
0.104 
0.104 

0.097 
0.097 

0.105 

0.100 
0.1 00 

0.100 
0.105 

0.105 

0.101 

0.101 
0.102 

0.0!" 

0.097 

0.097 



Properties obtained from standard J^-inch diameter test specimens, indi- 
\ idually cast in a permanent mold, and tested without machining oil" the 
surface. The compositions and/or heat treatment and the chill casting of 
ttian\ of th< alloys are patented. 

Brinell limits obtained from tests on commercial castings. For 122 and 142 
alloys, values apply to readings taken on \ ton head ^£~inch from ed and 
3 v-inch from gate on pistons having thicknc of head up to j^-inch. 
Thicker < lings, castings poured with sand core or poured in sand gi\ ■ 
lower values, the maximum decrea l»<-ing about 20. 

(*) Young's modulus of elasticity is approxim ' l\ 10,300.000 pounds j" I 
square inch. 



66 



3> 



X> 



ALUMINUM COMPANY of AMERICA « 



« 



a 



TABLE 13 



MECHANICAL PROPERTIES SPECIFICATIONS FOR 
SHEET AND PLATE 2S, 3S, 4S, 52S 



SHEET 



Grade 

and 
Temper 



Tensile 

Strength 

Lbs. per 

Sq. In. 

Minimum 

Except for 

Soft (O) 

Temper 



Minimum Elongation** — Per Cent in 2 Inches 



250"- 
.204" 



2SO 

2SMH 

2S%H 

2SII 
3SO 

3SMH 

3S^H 

3S^II 

3SH 

4SO 

4S^H 

-tS^H 

4S%H 

4SH 

52SO 

52S^H 

52S^H 

52S%H 

52SH 



15,500* 

14,000 

16,000 

19,000 

22,000 

19,000* 

17,000 

19,500 

23,500 

27,000 

29,000* 

28,000 

32,000 

36,000 

38,000 

31,000* 

31,000 

34,000 

37,000 

39,000 



30 
10 

7 

* ft 

■ m 

25 
9 

8 

i • 

■ # 

18 
4 
4 



5-6 

Gauge 

203"- 

.162" 



7-9 

Gauge 

.161"- 

.114" 



30 
10 



20 

10 

8 



25 
9 

8 

9 ■ 

■ • 

18 
4 
4 

20 

10 

8 



30 

10 
7 
4 
4 

25 
8 
7 
4 
4 

18 
4 
4 
2 
2 

20 

10 

8 

4 

4 



10-16 

Gauge 

.113"- 

.051" 



17-20 21-24 
Gauge I Gauge 
.050"- .031"- 



30 
9 

7 
4 
4 

25 
7 
6 
4 
4 

18 
3 
3 
2 
2 

20 
8 
7 
4 
4 



032 



25 

7 
5 
3 
3 

23 
6 
5 
3 
3 

16 
2 
2 
2 
2 

20 
6 
5 
4 
4 



.020 



25-28 

Gauge 

.019"- 

.013" 



29-32 

Gauge 

.012"- 

.008" 



20 

5 
4 

2 
2 

20 
5 
4 
2 
2 

14 
2 
2 
1 
1 

18 
6 
5 
3 
3 



15 
4 
3 
1 
1 

20 
4 
3 
1 
1 

10 
1 
1 
1 
1 

15 
5 
4 
3 
3 



1.3 

• * 

2 
1 

1 
18 

* * 

2 
1 
1 



33-36 

Gauge 

.007"- 

.005" 



15 



1 

1 

16 



1 
1 



2S, 3S, 4S, 52S, As Rolled 



PLATE 

quired 



r\ /xj /tr / Physical properties same as for ^-inch sheet in same alloy and 
O, 34H, y 2 ti j temperi (See Table 33for temper available in various thicknesses.) 

MAXIMUM AND MINIMUM COMMERCIAL THICKNESS OF 

FLAT AND COILED SHEET IN ALL TEMPERS 



Temper 



FLAT SHEET 



Thickness — Inches 



COILED SHEET 



Thickness — I nches 



Maximum 






h 

y 2 n 

H 



Minimum 



0.250 
0.250 
0.250 
0.162 
0.128 



0.010 
0.016 
0.010 
0.010 
0.010 



Maximum 



Minimum 



0.102 
0.102 
0.081 
0.051 
0.102 



0.005 
0.025 
0.010 
0.005 
0.005 



♦Maximum. So specified to insure complete annealmg. 

*In the KH and V 2 U tempers, coiled sheet may have an elongation one per 
cent lower than the above values. Test specimens taken parallel to direction 
of rolling from flat and coiled sheet in 34 H and HH tempers. 



67 



ALCOA ALUMINUM and ITS ALLOYS 



« « 



« 



TABLE 14 



MECHANICAL PROPERTIES SPECIFICATIONS 
FOR 17S ALLOY PRODUCTS 



Material 


Dimensions^) 
(Inches) 


Tensile 

Strength 

Pounds per 

Square Inch 

Minimum 

Except for 

17S-0* 


Yield 

Strength 

(Set =0.2%) 

Pounds per 

Square Inch 

Minimum 


Elongation 

(Minimum) 

Per Cent in 2 

inches or in4D** 


17S-0 


0.010—0.500 


35,000* 


^ 


12 


Sheet and Plate 










17S-T 


0.010—0.020 


55,000 


32,000 


15 


Sheet and Plate 


0.021—0.040 


55,000 


32,000 


1 nr*** 




0.041—0.128 


55,000 


32,000 


18 




0.129—0.258 


55,000 


32,000 


15 




. 259—0 . 500 


55,000 


32,000 


12 




0.501—1.250 


55,000 


32,000 


10 


17S-RT 


0.020—0.031 


55,000 


42,000 


10 


Sheet 


. 032—0 . 036 


55,000 


42,000 


11 




0.036—0.188 


55,000 


42,000 


12 


Alclad 17S-0 


0.010— 032 


30,000* 


»*■..* 


8 


Sheet 


. 033—0 . 064 


30,000* 




10 




0.065—0.250 


30,000* 




12 


Alclad 17S-T 


0.010—0.020 


50,000 


28,000 


13 


Sheet and Plate 


0.021—0 128 


50,000 


28,000 


16 




0.128—0.250 


50,000 


28,000 


13 




0.251—0.500 


50,000 


28,000 


11 


Alclad 17S-RT 


0.020— 031 


50,000 


37,000 


8 


Sheet 


. 032—0 036 


50,000 


37,000 


9 




0.037—0 188 


50,000 


37,000 


10 



Wire, Rod, Bar and Shapes 



17S-0 Wire 

17S-0 

(Rolled or extruded) 

17S-T Wire 

17S-T 

Rounds, squares, 
hexagons, octagons, 
(rolled j 

17S-T 

Rectangular bars 

17S-T 

Structural shapes 
(rolled J 

17S-T 

Extruded shapes 



up to 0. 124 



0.125—8.000 
up to 0.124 



0.125 
0.751 
3.001 



750 
3 . 000 
8 . 000 



up to 750 
751— 3 000 



35,000* 

35,000* 
55,000 

55,000 
53,000 
50,000 

53 , 000 
50,000 



50,000 



50,000 



30 , 000 
30,000 
28 , 000 

30,000 
28 , 000 



30 , 000 
35 , 000 



16 



18 
18 
16 

16 
16 



16 



12 



68 



, . . AH IMINIJM COMPANY of AMEIth V . 



TABLE 14 \ll.cil\M(.\l. PROPKHTIKS SPECIF* iTIOW 

FOB L7S \LLO\ PRODI GTS Continued 



\1 ii In i 



I llllM (l \H tf] 

( I M. I,. H) 



I Pfl Aile 

ill ftiitfth 

Mound p 

] i h 

\l 

I 
I 



I 

i 



■ 



I iiIuiik 



1?^ O 

17S-T 



us hi 



I mi <j in; 



I " 



I7> I 



Ml 



1 t I \m I 
ovei I l im< 
ovw I ' • D iiu'l 



Ml 



up i ■ ■ I 






i I 

55,000 



1 



to 



000 



10,0 

oo 

00 



>u 



\l,i\ iii So ipe< iln <l '" in mri ■ -■■■!-!• i- inneulin 

M Foi wit.- rod and bai tin ~ iu length i I tiui I im 

lance between parallel *uH r.s « \< t«p( win n n lln 

Km- sIhtIn loss ili. m 30 ui< I" > with lonu iti m h 'II I"' IM 



I I 






1 1 1 I' ..I Sheet and Plate I Iu. kr 

I . .i \\ ii Rod and Bai Dinim t 

*urf > 
l-.u rubuiK i Mil Hide I >i.un.-i 
For I mi uinxs I Mumetei or tin. ktn 



i i > i I 1 1 






in 



i 






b 



» 



» 



>/ 



ALCOA ALUMINUM and ITS ALLOYS 



15— MECHANICAL PROPERTIES SP 

FOR 24S ALLOY PRODUCTS 



Material 



Dimensions^) 
(Inches) 



Tensile 

Strength 

Pounds per 

Square Inch 

Minimum 

Except for 

24S-0* 



Yield 

Strength 

(Set=0.2%) 

Pounds per 

Square Inch 

Minimum 



Sheet and Plate 



24S-0 



24S-T 



24S-RT 



Alclad 24S-0 



Alclad 24S-T 



Alclad 2*S-RT 



0.010—0.500 
0.010— 0.020 
0.021—0.040 
0.041— 0.1 28 
0.129—0.250 
0.020—0.031 
0.032—0.036 
0.037—0.188 
0.010—0.032 
0.033— 0.0G4 
0.005—0.250 
0.010—0.020 
0.021—0.128 
0.129—0.250 
020— 0.031 
. 032—0 . 040 
0.041—0.188 



35,000* 

(>2,000 

02,000 

02,000 

62,000 

05 , 000 

65,000 

65,000 

30,000* 

30,000* 

30,000* 

56,000 

56,000 

56,000 

58,000 

58,000 

58,000 



Wire, Rod, Bar and Shapes 



Tubing 



40,000 
40,000 
40,000 
40,000 
50,000 
50,000 
50,000 



37,000 
37,000 
37,000 
46,000 
46,000 
46,000 



cc c 

be c 

a* 



* 



a 



00 

s 

- 



a 

3 
| 

3 



12 
15 

18 

15 

10 

11 

12 

8 

10 

12 

13 

16 

13 

8 

9 

10 



24S-0 Wire 


up to 0. 124 incl. 


35,000* 




m m 


24S-0 










f Rolled or e \ t ruded > 


. 1 25—8 . 000 


35,000* 


....•* 


16 


24S-T 










Rounds, square, 










octagons (rolled) 


0. 125 — 8. 000 


02 , 000 


40,000 


16 


24S-T 










Rectangular bars 


up to 8 x 4 


62,000 


40 , 000 


14 


24S-T 










Extruded shapes 




57,000 


42,000 


12 









24S-0 


All 


35,000* 




# 


24S-T 


14 to 1 incl. 


62,000 


42,000 


16 




over 1—134 incl. 


62,000 


42 , 000 


14 




over 134 — 8 incl. 


62,000 


42,000 


12 



*Maxiniun). So specified to insure complete annealing. 
**For wire, rod and bar the gauge length is four times the diameter or 
distance between parallel surfaces except when a Hat test specimen is used. 
***For sheets less than 30 inr I wide, elongation shall be 18% in 2 in. 
(*) For Sheet and Plate = Thick n s. 

For \\ ire, Hod and Bar —Diameter or least distance between parallel sur- 

fac 

For Tubing = Outside Diameter. 



: 






» • » ALUMINUM COMPANY of AMERICA « 



« 



« 



TABLE 16— MEG! 


IANIGAL PROPI 


iRTIES spi 


3CIFICATK 


DNS 


FOR 5 IS ALLOY PRODUCTS 






Material 


DimensionsC 1 ) 
(Inches) 


Tensile 

Strength 

Pounds per 

Square Inch 

Minimum 

Except for 

51S-0* 


Yield 

Strength 
(Set=0.2%) 
Pounds per 
Square Inch 

Minimum 


Elongation 

Per Cent in 2 

inches or in4D** 

Minimum 


Sheet and Plate 










51S-0 


0.010—0.020 


19,000* 




20 




0.021—0.128 


19,000* 




22 




0.129—0.500 


19,000* 




25 


51S-W 


0.010—0.020 


30,000 


16,000 


18 




0.021—0.250 


30,000 


16,000 


20 




0.251—0.500 


30 , 000 


16,000 


18 


51S-T 


0.010—0.020 


45,000 


35,000 


8 




0.021—0.250 


45 , 000 


35,000 


10 




0.251—0.500 


45,000 


35,000 


8 


Wire, Rod, Bar and Sha 


ipes 








51S-0 Wire 


up to 0. 124 incl. 


19,000* 




• ■ 


51S-0 










All sections (rolled 










or extruded) 


0.125—8.000 


19,000* 




20 


51S-W Wire 


up to 0. 124 incl. 


30,000 


«••••* 


ft • 


51S-W 










Rolled sections 


0.125—3.000 


30,000 


16,000 


16 


51S-W 










Extruded sections 


All sizes 


26,000 


16,000 


14 


51S-T Wire 


up to 0. 124 incl. 


45,000 




• * 


51S-T 










Rolled sections 


up to 3 . 


43,000 


35,000 


8 


51S-T 










Extruded sections 


All sizes 


42,000 


38,000 


8 


Tubing 










51S-0 


H— 8 


19,000* 




* ft 


51S-W 


K-s 


30,000 


16,000 


14 


51S-T 


K-z 


45,000 


35,000 


8 


Forgings 




up to 4 


40,000 


30,000 


8 



*Maximuoi. So specified to insure complete annealing. 

**For wire, rod and bar the gauge length is four times the diameter or dis 
tance between parallel surfaces (4D) except when a flat test specimen is ust <i 
( l ) See ( l ) page 73. 



71 



ALCOA ALUMINUM and ITS ALLOYS « 



« # 



TABLE 17 



MECHANICAL PROPERTIES SPECIFICATIONS 
FOR 53S ALLOY PRODUCTS 



Material 



Dimensions^) 
(Inches) 



Ten8ile 

Strength 

Pounds per 

Square Inch 

Minimum 

Except for 

53S-0* 



Yield 

Strength 

(Set=0.2%) 

Pounds per 

Square Inch 

Minimum 



Sheet and Plate 



53S-0 



58S-W 



SS-T 



0.010—0.032 

0.033—0.128 

0.129—0.500 

0.010—0.020 
0.021—0.249 
0.250—0.500 

0.010—0.031 
0.032—0.500 



19,000* 
19,000* 
19,000* 

28 , 000 
28 , 000 
28,000 

85 , 000 
35 , 000 



\\ ire. Hod, Bar and Shapes 



10,000 
10,000 
16,000 

28,000 
28 , 000 



s *^ i mm 1 

5. o 



* 

Q 

* B 
a a 



a - 
i 

« 

a 



20 

22 
25 

18 
20 
18 

8 
10 



58S-0 Wire 


up to 0. 124 


19,000* 




• • 


5SS-0 (Rolled) 


0.125—3 000 


19,000* 




20 


5SS-0 Extruded 




19,000* 

25,000 




18 


53S-W Wire 


up to o. 124 


* • 


53S-W 










Rounds, squares, 

hexagons, octagons, 
rectangles (rolled) 


1 25—3 000 


25 , 000 


1 4 , 000 


20 


53S-W 

Shapes (rolled or 
extruded j 




25 , 000 
32,000 


1 4 , 000 


18 


53S-T Wire 


Up to 124 


• • 


53S-T 










Rounds, squares, 
hexagons, octagons 
(rolled; 


125 8.000 


32 , 000 


25 , 000 


10 


53S-T 
Rectangles (rolled 1 

53S-T 

Shapes (.extruded or 
rolled; 


up to 0.750 

0.751 3 000 


32,000 
32,000 

32,000 


25 , 000 

t:> , ooo 

25 , 000 


16 
14 

10 


/ 




A Vr 



72 



> ALUMINUM COMPANY of AMERICA « 



* 



TABLE 17— MECHANICAL PROPERTIES SPECIF! 

FOR 5SS ALLOY PRODUCTS— Continued 



Material 


Dimensions^) 

(Inches) 


Tensile 

Strength 

Pounds per 

Square Inch 

Minimum 

Except for 

53S-0* 


Yield 

Strength 

(Set = 0.2%) 

Pounds per 

Square Inch 

Minimum 


* 

- z 


Tubing 










53S-0 
58S-W 

53S-T 


ah 

3^ — 1 incl. 
over 1 — \ l /2 incl. 
over \}^ — 8 incl. 

}/± — 1 incl. 
over 1 — \]4, incl. 
over \]4, — 8 incl. 


19,000* 

28,000 
28 , 000 
28,000 

35,000 
35,000 
35,000 


14,000 
14,000 
14,000 

28 , 000 
28,000 
28,000 


18 
20 
18 

16 

14 

12 



♦Maximum. So specified to insure complete annealing. 

♦♦For wire, rod and bar the gauge length is four times the diameter or dis- 
tance between parallel surfaces except when a flat test specimen is used. 

0)For Sheet and Plate = Thickness. 

For Wire, Rod and Rar = Diameter or least distance between parallel 

surfaces. 
For Tubing = Outside Diameter. 
For Forgings = Diameter or thickness. 



73 



ALCOA ALUMINl M and ITS ALLOYS 



TABLE l CHEMICAL COMPOSITION AND TYPICAL 
MECHANICAL PROPERTIES ' <H l)!K-<:\sn\(i ALLOYSO 



All.-N 








<:..»» 


l:{ 




1 


9 


82 


14 


83 


2 


85 


4 


93 


1 



Nominal Chemical 

< lompoai t i<>n( s ) 



(I 



o 





Silicon 


Nickel 




12 o 


• 




3 '» 






5 






9 






5 o 






2 


\ 



I Itimate 
Strength 
Lbs. per 

S<] lii 


I^longatioo 

1\t ( e ill 

tn 2 1 nrlirs 


Iirim-ll 

1 [ardneas 


33,000 


1 3 


so 


,000 


1 3 


70 


44,000 


o 4 


100 


80, 000 


3 r > 


60 


8."i. 000 


3 o 


70 


32,000 


1 


HO 



rensil) proper ti are average I values obtained from A. S.T.M. standard 
""""l ' i i men, ', i neb in diameter. Brinell Hardm ob 

lained from \ ^ I M standard flat <!»< isi test ,s| nen inch Unci 
using i kg. load and 5mm. ball, 

*< modulu of elasticity for all of the above alloys is approximate!) 

I (l ' 000 I N Hjntj i ,. i s(|i|,i|. i f i. Ii 

I'" comp ition and ehill easting of many of th«'sc (illo) m patented. 



PABLI 10 Ml.i.lhMi \i PROPERTIES SPECIFICATIONS 

I <Ht Ml MINI M \\Am\ FOHC;INi 



M 



■ 



IKS. 


1 
I 


t 

* 


1 


7(1 


I 

1 



i j u r 1 1 

I i I I M I i 

I tn !> 





KM) 


1 


KMI 


r r 


►00 




00 


J( 


Ml 


t 


00 


4' 


I0U 


43 


■ 







; *f 



\ M-lii Si t riiyl It 

<sm or'; , 

I '< hi ml 
S<|ui.n huh 

M ihj itMi rn 



100 

80,000 

,000 

I 000 

100 

4<t >0 

31 

I 

40 (j 



Minimum 

I 1'in^iitKili 

I'fi ' <-nl 



ii Z 



In. I 






» » 



10 

14 

K 

16 

1* 



J* 
I* 



111 IIH-II 

1 1 urcliii -»• 

00 I r I •),,,,,! 

ball 

M M j § 1 1 1 1 1 i 



f 



Up 1" 1 llll 



in c j j ; « r 1 1 < l« r <,f li.j 



n< 



J 30 

90 

ieo 






.mi, roi u,«- / 

f 1 ii. i. i 



ni of < Mag. -hall in (nui iifjMK 



i < 



llll 



I 



I 






» 



ALUMINUM COMPANY of AMERICA 



* 



I 



TABLE 20— COMMERCIAL TOLERANCES FOR SHEET AND PLATE 

ALL ALLOYS 

Thickness Tolerances 

FLAT SHEET— ALL ALLOYS; COILED SHEET— 17S, ALCLAD 17S, 24S, 

ALCLAD 24S, 25S, 51S 



Thickness 



I'.. I. -ranee (Plus or Minus) in in<h<-. . •», ■, pt where 
shown as per cent of nominal thickness (1 ) 



It & S 
' <auge 



3-8 

0-10 

U-12 

13-10 
17-18 

19-25 
20-30 



I riches 



Width 

lip lo 

18" 
Incl. 



0.24!) tO 

(i 128 to 

0!)1 to 
0.072 to 
0.30 to 
030 to 
017 lo 



129 
it 092 
() 073 

0.051 

0.037 

0.018 
0.010 



Width 

Over 18" 
to \U" 

[ ncl. 



Width 

Over 36" 

to 54" 

Incl. 



4%T 

0.00 I 
, 003 
. 0025 

(> 002 

0.0015 

0015 



4%T 

0.0045 

o 003 

0.003 
. 0025 

002 
0015 



Width 

Over 54* 

to 712" 

III! I 



Width 

Over 7 
to 90* 

I IX I. 



5 %T 

" ' 
O.oot 

0(11 

it 003 

0.0025 
. 002 



v r 

0.O07 

(I me, 

005 

it 001 



7%T 

HO!) 

1 8 

it O07 



Width 

0v< <•>()" 

to 102* 
Incl. 



I 

Mill 



f • 






i OILKI) SHI ET 2S, 3S, 4S 



Thickness 



I olerance (Plus or Mums) in inch< 



B & S 

< >augc 



I riches 



10-11 

12 
13-16 

17 
1 8-20 
21-24 
25-2!) 
30-32 
-34 



n 102 to 
0.090 to 
072 to 
0.050 to 
0.040 to 
0.029 to 
0.018 to 
010 to 
0.007 to 



0.091 
0.073 
0.051 
o 041 
0.030 
0.019 
0.011 
0.008 
0.006 



Width Op to 

12* 

Incl. 



0.003 

o 003 

0.002". 

0.0025 

0.002 

0.002 

0.0015 

0.001 

0.001 



Width* Ov< 

12" to 2 1" 
Incl 



Widih- 

( ) , t-r 
2 j» 



o 





o 










003 
003 
003 

00 2,'. 

0i 

DO-2 

002 
0015 

001 



0.004 

i, i,i. ; 

003 
0.0025 

125 

i) iin-2 



•Tolerance applies up to Maximum Width shown in Tal.le 31. 

PLATE— ALL ALLOYS 



Thickness 

(I nches) 



Tolerance (Plus or Minus) in per cent of nominal thickness 



Width Up 

to 54* 

I IH I 



3 000 to 1 .001 
I 000 to 0.501 

o 500 to o 375 

0.374 to - ">0 



Width Ovei 

r t«> 72" 

I ncl 



3 
I 

5 

5 



I 
6 



Width Over 
j to 'JO* 
Incl 



1 



<A 1 1 i > . 

120" 

I ncl 



5 

7 
8 






75 



» » 



ALCOA ALUMINUM and ITS ALLOYS « 



TABLE 21— COMMERCIAL TOLERANCES FOR SHEET AND PLATE 

ALL ALLOYS 

Width, Length, Diameter 

FLAT SHEET— SHEARED 

Width Tolerance (Plus or Minus), Inches 



Thickness 


Width 

14" to i" 

Incl 


Width 

Over 1" 

to 18" 

Incl. 


Width 

Over 18" 

to 36* 

Incl 


Width 

Over 3n* 

lo 51" 
Incl 


Width 

Over 51" 

lo 72" 

1 ncl . 


W r id th 

Over 72" 

to 102" 

1 ncl 


B & S 


1 riches 


3-9 

10 34 


it 249 lo 0.103 
(i 102 to 0.006 


a 


Hi 
He 


Hi 


He 

^8 


H* 
Hi 


He 



Length Tolerance (Plus or Milium), Inches 



Thick iHtm 



All ( Juntos 



Leogl b 

I p to 18" 

I ncl 



■iG 



Length 
Over 18" to 

18" Incl 



Hi 



Length 
Over 48" tO 

120" Inch 



8 



Length 

Over 120" to 
180" Inch 




length 

Over 180" to 

540" Inch 



1 



-l 



I OILED SHEET SHEARED 



HA S ( j gi 
10 tO 34 





W if i t li Tolerance (Plus <ir 


M in us), Inches 




'1 Inckn 


Width 

1 , " to 

3" Incl 


Width 

Over 3" to 
24" Incl 


Width 

Over 

21" 


* 


1 iteheM 




(i 102 to 006 


!^4 


^ 


Hi 



sill I I CIRCLES SHEARED 

Diameter Tolerance (Plus or Minus), Inch' 



■ 



IlnckiieBH 



All ( raug< 



I diameter 

" lo 18" lucl 



] 4<L 



I )iame1 • 

Over 18" 



\ii 



sin f i wo PLATE SAWED 

Dimension Tolerance (Plus or Minus), Inches 



I luck iM-ftB 

O fiflo 



I p to 3 



l UfiM ions 

I p io 10* Incl 

] 4i 



I >i mansions I Dimensions 

Over 10* to in" Over 56* to 60" 
Incl Incl 



',, 



'Hi 



Dimension!! 

Oviv60 # to]S0* 

Incl 



% 



PLATE SHEAR! D 

Width und Ijenglit I oI<t.u,. (Plus only), lochi 



• 



1 hirkneM* 

(Inclf 



1 to 1 001 

] 000 to i] 

to i . 




I a <<yi\> I ol«ron< 



\a ii(.'ili ( r 

12 ti to 20 ft 

He 

7 Z 



Length ■ 

ill to 4 •> It 






y+ vsX >lf ri** with tirade a ud U ol allov Maximum thickness \ .* 

I u-rijfjer i* J in< ( jnmoo all <>> j 5 inch icker plate must be sawed 
•Maximum width I inches I > r ****** 0.250 to I inofai Uu um width is 

or triickiJfttBQs < 6 to K) and j n !,-, i « [„-> „ 

'"V ' uger plates, 18 . ies »* tin u ruunu width iredpla" nan 

widths mu sa»f«: 



:• 



» 



ALUMINUM COMPANY of AMERICA « 



« 



TABLE 22— COMMERCIAL TOLERANCES FOR 

EXTRUDED PRODUCTS 

SHAPES 

Cross-Sectional Tolerances 






Dimensions — Inches 



2S, 3S, 4S and 17S,24S, 51S, 

53S — Not Heat Treated 

Plus or Minus — Inches 



up 

0.126 
0.501 
1.001 

2 . 001 

3 . 00 1 
4.001 
5.001 



to 0.125 
to 0.500 
to 1.000 
to 2 . 000 
to 3.000 
to 4 . 000 
to 5 . 000 
and over 



.007 
.010 
.015 
.017 
.020 

.025 
. 030 

.035 



17S, 24S, 51S, 53S 

Heat Treated 

Plus or Minus — Inches 



.010 
.015 
.020 
. 025 
.030 
.035 
.045 
.060 



ROUND, SQUARE, RECTANGULAR, HEXAGON 



Dimensions — Inches 



up to . 500 
0.501 to 1.000 
1.001 to 2.000 
J. 001 to 3.000 
3.001 and over 



All Grades — As Extruded or Heat Treated 

Plus or Minus — Inches 



.007 
.010 
.012 
.015 

.018 



EXTRUDED AND DRAWN ROD 



Dimensions — Inches 



0.375 to 0.500 
0.501 to 1.000 
1.001 to 2.500 



Length — Feet 



Up to 13 

Over 13 



All Grades — As Extruded or Heat Treated 

Plus or Minus — Inches 







Length Tolerances 



Tolerance — Inches 



0, 

o,+ 





Standard Structural Shapes, rolled or extruded, (Channels, I-beams, Angles 
Z's and T's) in which the thickness of web, flange, or leg is not less than 140 
inches are manufactured to a tolerance of 2H per cent (plus or minus) on 
the nominal weight of the section. Actual weight shipped is invoiced. 



77 



ALCOA ALUMINUM and ITS ALLOYS « 



TABLE 23— COMMERCIAL TOLERANCES FOR TUBING 

1. ROUND TUBING 

Diameter Tolerance 











Tolerance in Inches (Plufl or minus) 






Individual Measuremeni of DiamHer 


Nominal I )iarnel 


(T 




Mean Diameter* 

ur Pi-tape meas- 
urement - 2S iS, 


(oul-of-roundness) 




I riches 






2S, 3S, 52S, except 


17S, 24S, 51S, 538, 










its. 24S, r , is. 


(1) Soft (O). or 


2S-6, 3S-0, 52S-0, 










52S, S.iS 


(2) thin wall** 
tubes 


and thin wall** 

tul>es 




%u> 


H 


incl. 


008 


003 


0.00G 


Greatei 


than ' to 


l 


incl. 


(I 004 


004 


0.008 


< ireater 


than 1 t<> 


2 


in< 1. 


o 005 


o 005 


010 


Greater 


than L 2 lo 


:i 


incl. 


006 


0.006 


0.012 


( ireater 


than 3 to 


5 


incl. 


oos 


0.008 


i) 016 


(ireater 


than 5 to 


6 


incl. 


010 


010 


0.020 


Greater 


than (i to 


8 


incl. 


015 


01 5 


080 


(ireater 


than h to 


10 


incl. 


(i 020 


20 


0.040 



*M< ;m Diameter i^ the average of an) two measurements of diameter taken 
at right angles to each other a1 an) point along iIh* Length of the tube, 
rhin v» all I s than of diameter. 

Wall Thit kness Tolerance 



I oleraoce in Inches (Plus or minu 



% i mioal \N all I hi< k I ) 

(Inch) 



Mi ;m 4 \\ ;i 
I hi< km 



IikIiv idual m< isuriiuifils 
of \\ all 1 hirkncHH 



I '- : IS 51S, 538 



ITS 24£ 






oio to 








086 to 


049 





050 to 


120 





121 to 


208 





204 to 








-oi to 


' 


< 


. o 


00 



o oo 

003 

(J ooi 

(j 00 
008 
012 

032 



10' 

10' 

H 

10' 

10' 



f 



of T 

of T 
of T 
ofT 

of I 

of T 



io'; of T 



">2S 
















002 

003 

00 1 

00 

008 

012 

52 



*M< ill ihi< ki s i s the average of the two measurement! taken at opp< '< 

no's of an> diameter of the tube. 

lyen^ih Toleram < Ml Alloys 



I*Iub I hi I in li«a 



Notional <>« 1 )i;, 



ll 



i 



■ I . - 



I 
Ovei 



t< , ■ x< lusiv 

, to 2 iri(lusi\ 
real hni 2 lu :', im lusi\ 

re b i than 3 to 10 inclw>i 



J K 



Va 

He 

Va 






i • a 



ALUMINUM COMPANY of AMERK \ 



■ 



I Mil. I. t \ I u\1\1l \U A M. M'lll'.\ S( l Mill hi « . 



ii ii:i.fii< I 



Ml .11- .11 i 



f 












I IijUmI* I I 



, IfJ I 






' 



Ml I 



I I 



M ii I i m u' n i ! I n I 'i 

III i ill ' I 



I'iri 



i ii 






M 



I 









1 






I - 



• i ' in 

* « j ! I ' i 
( ,i . - 

• utrr lh«i 





. III. 1 
















1 










1 






1 1 










1 




1 ' 










H 


t * J 
















K 





I 



I Mil K t* i m\i mi i i vi i -i i i mi 

I 1 1 it M I ; \ I If AIM v \ I i • 



\a I h i\ 



I l I » i I » I \ i \ l ; l i 






riii k f i • • i 



U || >1 1| 

I th of 

I r 1 ig th 

I [» r in. I 

< III* In 

iiuu % U 



i I 



.v i 



• 







.il t tiii k 












fill* t 



\ I 

I 












I 



!A U 






\\ I i I r tipm 

{ in* tie* i Li 






i 









* 



• 



\ tual w 

olrraiu % 



I ► 



tit ifc 

nU i 






I »• 









hf 






ALCOA ALUMINUM and ITS ALLOYS 



« 



« 



« 



TABLE 25— COMMERCIAL TOLERANCES FOR WIRE, ROD 

AND BAR— ALL ALLOYS 

ROLLED ROD ROUND (ALL ALLOYS) 



Diameter 


Tolerance — I nches 


Diameter 
Inches 


Tolerance — I nches 


Inches 


Plus 


Minus 


Plus 


Minus 


0.375 to 1.500 
1.501 to 3.499 


0.015 

0.008 


0.015 
0.008 


3.500 to 5.000 
5.001 to 8.000 


14 

He 


l 4i 



ROLLED RAR (ALL ALLOYS) 
(Squares, Hexagons, Octagons, Rectangles) 



Least Distance 

Across Flats 

Inches 



up to . 500 

0.501 to 0.750 
0.751 to 1.000 
1.001 to 2.000 
2.001 to 3.000 



Tolerance — Inches 
Plus or Minus 



0.006 
0.008 
0.012 
0.016 
. 020 



Width 

(of Rectangles) 
Inches 



up to 1 . 500 

1.501 to 4.000 
4.001 to 6.000 
6.001 to 10.000 



Tolerance — Inches 
Plus or Minus 



Hi 



3 




He 



COLD FINISHED ROD AND RAR (ALL ALLOYS) 

(Rounds. Squares, Hexagons, Octagons) 
Rectangles up to 2.75" wide (provided area is not greater than 3 square inches) 



Diameter or 

Distance Across Flats 

Inches 



up to 0.064 

0.065 to 0.500 
0.501 to 1.000 
1 .001 to 1.500 
1.501 to 2.750 



Tolerance — I nches 
Plus or Minus 



Rounds 



0.001 
0.0015 
. 002 
. 0025 



Square 
Hexagons 
( >ctagons 










0015 
002 
0025 
003 



Rectangles 



0.0015 
0.002 
. 0025 
. 003 
0.005 



COLD FINISHED RECTANGLES* 2S, 3S, 52S and 53S 



Thickness 
Inches 



up to . 250 
0.251 to 0.500 
0.501 to 0.750 
0.751 to 1.500 



Tolerance — Inches 
Plus or Minus 



o 







0025 
0035 
005 

008 



Width 

Inches 



up to 1.500 
1.501 to 4.000 



Tolerance — I nches 
Plus or Minus 



x 4i 

] H2 



* Widths greater than 2.75 inch and /or area 
Maximum dimensions 1.5 inch by 4 inch. 



greater than 3 square inches 



80 



. . . Ml MINI \l COM I' \ N N a) \ \l I It l< \ 



I Mil I. Ui\t\ll IK I \l. MM | |i \ V I \ ,M l/l I .1 

l((H fOH Hi »l I IM HOI Mm « »|t J It I -I \HI \ ti 

M < I \ II \l I \l I ' 






I ><!• I III IM 
II III . 



lit, 

| | | | | | 



tl| 

H 



I I. 
i I. 
On I 



III 1 i HI 

I I II I 

II In I 



i i 



■ 






I 






I 

1 



I 



I Mil I 11 

I I \ 



COM Ml If I M I • i| lit \ (CI V Ml |/l 



II I Ml 1 Will I v i ' I i v I i 

III V\ IHI \M MM 



II- I il) 



1 



< 



.i 



I. 



i * > 



i 



I I v I I I . I I J . Mil 

i M II 



III' I M 



)l|| 



m 



|J ii I 

II iii| 

ii I MM 

1) 



II 



II 

I ' . 



I I. . 

I 

1 






IMI I 

i i 






i 












i 









In. 



I > I 

1 'm* 



II 

• I 












I 





















ALCOA ALUMINUM and ITS ALLOYS « 



« 



TABLE 28— MAXIMUM COMMERCIAL SIZES OF 

FLAT SHEET 2S AND 3S 



Thickness 
Inches 



-2.30-0 163 
0. 165M). 129 
128-0 1-2(1 
L25-0.0! 

i) 093-0 064 



(i 003-0 040 



o OS9-0 032 



o 031 0.020 



o 019 0.014 
oi:; o 010 
009 o 005 



Rolling Limits 



Width 
Inch < 



102 
102 
102 
1 2 

90 




66 
60 



Length 
Feet 



24 
24 

24 
24 

24 

16 

20 
30 




4S 

36 
30 




10 

Ki 

12 

12 

8 



Stretcher Limits 



Width 
Inchrs 



90 

90 
90 
88 
86 



70 



* 
* 



Length 
Feet 



24 
24 

24 
24 
24 



20 



* 



Diameter 

of 

Circle 

I nches 



Temper 
Range 



96 
96 
96 
90 
90 



84 



GO 



60 



48 

36 

30 



o to y 2 \\ 

o to %\\ 

O to H 
() to H 

O to II 



toH 



O to 11 



to II 



() to H** 

to II** 
() to H 



'Greater than rolling limits. 

The minimum thickness for sheet in the Ijll temper is 0.016 inch. 

TABLE 20— MAXIMUM COMMERCIAL SIZES 01 STRONG ALIXN 

FLAT SHEET 17S, MS*, *5S, 5 IS, 5SS, ALCLAD 17S, AND 

ALCLAD 24S* 0, W, AND T TEMPER 



Thickness 


Width 


Length 


Diameter 


Stretcher 


Inches 


Inches 


J 


J n 


Maximum 


. £50 to 120 inclusive 


102 


24 


96 


90" x 24' 


. 1 1') to 094 inclusive 


102 


24 


96 


88" x 24' 


098 to 004 inclusive 


90 


24 


90 


86" x 24' 


003 to Oal inclusive 


72 


18 


72 


76" x 20' 


.050 to 040 inch) 


60 


18 


60 


76" x 20' 


039 to 032 inclusive 


48 


18 


48 


70" x 20' 


031 to 020 inclusive 


42 


10 


42 


70" x 20' 


019 to 014 inclusive 


30 


14 


36 


70" x 20' 


013 to oio inclusive 


28 


14 


28 


76" x W 



*V\i<ji ei than GO" not strict!) cotnmerciaJ in £4S and Alt lad t\^ 

orders for gi r widths in tkickne 0,051* to O.£50* may l>< * 

tentative!) ontin^ent upon th<- d< elopmenl of sati factory commercial 
iiiaoui taring pra< tice. 

M iniurn siz tnrieah'd sheet 0" a ±\ 



82 



ALUMINUM COMPANY of AMERICA « 



« 



TABLE 30— MAXIMUM COMMERCIAL! SIZES OF FLAT SHEET 

4S AND 52S 



Thickness 
Inches 


Rolling 1 


Limits 


Stretcher 
Limits** 


Diameter 
Inches 




Width 


l.i'M^lh 


Width 


Length 


Temper Range 




Tnchesft 


Feet 


Inches 


Feet 






0. 250-0. 103 


102 


24 


90 


24 


96 


O to 3^H 


0.162-0. 129 


102 


24 


90 


24 


96 


O to %H 


0.128-0.126 


102 


24 


90 


24 


96 


toH 


0.125-0.094 


90 


24 


88 


24 


90 


toH 


0.093-0.081 


84 


24 


* 


* 


84 


toH 


0.080-0.064 


72 


20 


* 


* 


72 


OtoH 


0.063-0.040 


60 


14 


* 


* 


60 


OtoH 


. 039-0 . 032 


48 


14 


* 


* 


48 


O toH 


0.031-0.022 


42 


12 


♦ 


* 


42 


OtoH 


0.021-0.014 


36 


10 


* 


* 


36 


to H*** 


0.013-0.010 


28 


8 


1 * 


* 


28 


O to H*** 



*Greater than rolling limits. 

**Sheet harder than J^H cannot be stretched. 

***The minimum thickness for sheet in the quarter hard (^H) temper is 
0.016 inch. 

fWidths greater than 60 inches and/or weights of a single sheet greater than 
200 pounds are not strictly commercial in 52S alloy; orders for sheets great- 
er than these limits may be accepted tentatively, contingent upon develop- 
ment of satisfactory manufacturing practice. 

ffMaximum width of sheets in the hard temper (H) is 54 inches and in the 
three-quarter hard temper (%H), 60 inches. 



TABLE 31 



MAXIMUM COMMERCIAL SIZES OF COILED SHEET 

2S, 3S, AND 4S 



Supplied in coils, flattened and cut to length**, or in circles. 



Thickness 
(Inches) 



Width 
(Inches) 



0.102 
0.047 
0.029 
. 023 
0.018 

0.011 

. 009 
. 008 
0.007 



. 048 
0.030 
0.024 
0.019 
0.012 










010 
0085 
0075 
005 



42 

42* 

38* 

38 

36 

30 
30 
18 
14 



Available 
Tempers 



O toH 

O to 11 
O toH 

o, y 2 n, %h, h 

0, HH, %H, H 

o, y 2 n, %H, II 

O, MH, H 
O, %H t H 
O, %U, H 



*In the 3^H temper the maximum width is 4 inches less than this value 
which applies to all other tempers. 
**Flattened coiled sheet is not supplied in thickness greater than 0.081 inch. 



83 



» 



ALCOA ALUMINUM and ITS ALLOYS « 



TABLE 32— MAXIMUM COMMERCIAL SIZES 
Fiat Sheet 17S-RT, 24S-RT, Alclad 17S-RT and Alclad 24S-RT 



Width (Inches) 



Thickness 
Inches 



Lengths 14 feet 
to 18 feet 



0.188 
. 077 
. 042 
. 029 



. 078 
. 043 
. 030 
. 020 




TABLE 33— MAXIMUM COMMERCIAL SIZES 

TEMPERS— 2S, 3S, 4S PLATE 



AVAILABLE 



Thickness 
Inches 


Width 
Inches 


Length 
Feet 


Tempers 


2" and over 

Less than 2" to 1" 

Less than 1" to K" 


130(1) 
130(1) 
120(1) 


30(4) 
30(4j 
30(4) 


AsRolled(3)andO(2) 

As Rolled( 3 ), 0( 2 ), and ^H 

As Rolled(3), 0( 2 ), 34H and 3^H 



0) Circles in O, x /$\ and ^H temper and in thicknesses up to Y% inches in 
the as rolled temper, can be supplied in diameters up to 96 inches. 
Circles in the as rolled temper in thicknesses over ^g inch to 2 inches can 
be supplied in diameters up to 130 inches, 

( 2 ) Maximum size of annealed plate: 96 inches by 25 feet. 

( 3 ) As a result of the cooling of the plate while it is being rolled, there is 
some strain hardening of the metal, particularly in the thinner gauges. 
The average tensile properties of as rolled plate in thicknesses up to h /% 
inch are approximately the same as those of quarter hard plate. As the 
thickness increases, the properties approach those of the soft temper (0). 

( 4 ) Subject to the limitation that the maximum weight of an individual 
plate or circle is 2,000 pounds. 

XOTE: Flatness — 

Stretcher-leveled plate is supplied in thicknesses l /i inch to 1 inch, widths up 

to 90 inches, and lengths up to 38 feet, 

Plate wider or longer than the limits for stretcher-leveled plate in thicknesses 

x /i inch to 1 inch is supplied roller-leveled. 

Plate in dimensions greater than the stretcher- and roller-leveler limits (i.e., 

thickness greater than 1 inch is supplied as flat as can be obtained from 

the rolls). 

TABLE 34— MAXIMUM COMMERCIAL SIZES— STRONG ALLOY 

17S, 25S, 51S, AND 53S PLATE 



Thicknes> 

Inches* 



Over 1 

Va tO 1 



Width 
I riches 



120 
120 



Length 
Feet 



35 (4) (5) 

35 (4; (5; 



Diam- 
eter 
Inches 

96 
96 



Stretcher 
Maximum 



90" x 24' 



Tempers 



0(2), H, T, W(«) 
0(2), H, T, W(«j 



j Narrower widths can be obtained in longer lengths but should be taken up 
with the nearest sales otfice. 

) Maximum size of artificially aged plate (25S-T, 51S-T, 53S-Tj is 98 inches 
by 38 feet. 

Note on Flatness and Notes (2) and {}) of Table 33 apply also to this table. 



84 



* 



ALUMINUM COMPANY of AMERICA 



TABLE 35 
PLATE- 



MAXIMUM COMMERCIAL SIZES OF ALCOA TREAD 
STRETCHER LEVELED— 3S, 4S AND 17S ALLOYSO) 





Maximum Size 


Approximate 

Weight per Sq. Ft. 

Pounds( 2 ) 


Estimated Weight 


Thickness 
Inches 


Width 
Inches 


Length 
Feet 


per Sq. Ft. in Steel 
Pounds 


He 
He 


50 
60 
60 
60 
60 


24 
24 
24 
24 
24 


1.96 
2.84 
3.72 
4.60 
5.48 


5.69 

8.23 

10.79 

13.32 

15.89 



I l ) Alcoa Tread Plate can be furnished in 17S, 4S and 3S alloys, but 3S is not 
slocked. Tread Plate in 17S is furnished only in the heat-treated temper 
(17ST); in 4S it is furnished as rolled. Where maximum strength is desired, 
17S is recommended. 

(2) Values are for 3S and 4S. Multiply by 1.02 for 17S. 



TABLE 36— CONDENSED LIST OF COMMERCIAL 

OF 1 7S STRUCTURAL SHAPES 




EQUAL 
\NGLES 



UNEQUAL ANGLES 



Size 
I uches 



Kex 



i * 



He 

A 



Size 

Inchi's 



1 Xl 

l^xl^ 

\y A x\% 

2 x2 

2 1 ,x2H 

3 .\3 

3Ux3H 

4 x 4 

5 x5 



% x 
1 x 

1%X 

l^x 




Size 

Inclirs 



STRUCTURAL 
CHANNELS 



Depth 
I uches 




4 
4 



lMxi 
i3^xi 

134x134 
2 xi34 



2 
2 



xlH 



V>x\\ 




23^x134 

23^x2 

3 xVA 

3 x2 

3 x234 

33^x23^ 
33^x3 

4 x3 

4 xS l A 

5 x2H 

5 x3 

5 x3M 

6 x3 l A 
6 x4 



3 
4 

.3 
6 
7 
8 



CAR 
CHANNELS 

5 

6 

10 



I-BEAMS 
3 

4 
5 

7 
8 



TEES 



Size, Inches 
Flange Stem 



1 Xl 

IHxIK 

lAxiA 

2 x2 

l\ix%M 

2^x134 



3 
3 

-1 



x2^ 
xS 

x 4 



H-HEAMS 

4 



ZEES 

Deplh. Inches 

3 
4 

5He 



Many of the above sections are obtainable in several different (lange, web, or stem thick- 
nesses. Consult nearest sales oilice. 

Elements of sections are given in "Structural Aluminum Handbook" published by Aluminum 
Company of America, 

\hove list includes both Intruded and Rolled shapes. 

Maximum length in a heat-treated alloy — Extruded Shape 36 Feet 

— Rolled Shape 85 Feet 



85 



1 



\LCOA ALUMINUM and ITS ALLOYS 



« 



TABLE 37— RANGE OF COMMERCIAL SIZES OF ROUND TUBING 



Thickness 



Stubs 
Gauge 



• * 



2 



3 



# • 



4 



* * 



5 



6 



7 



8 



y 



Inches 



.500 
.484 
.480 
.468 

453 
.450 
.437 
.421 

406 

400 

390 

.375 

.359 

350 

.344 

.328 

320 
.312 

300 
.297 

.284 
.281 
.266 
.259 

.250 
.238 
.234 
.220 

.218 
.203 
.187 
.180 

.171 

165 

.156 

.148 



Minimum 

O.D. 

Inches 



HhW 
CO M^ 



2N 

*A 




2 

m 

IN 

IN 

VA 

l 




IN 

l 
l 




8 

N 

A 

A 



% 
"A 
A 
A 

A 

9 46 

i 
A 

7 /fe 




QQ0G 
io 



7% 

7% 
7 

7% 

7% 

7 
8% 

8% 

8% 
7 

8% 
10 

9 3 % 
7 

10 

10% 

7 
7 

102^ 

7 

10N 
10% 

7 

io% 

7 

10% 

7 

10^g 

10% 

ION 

7 

10% 

7 

ION 

7 



O 

i 

-? 

r 

o 

i 



7% 

7% 

7 

7% 

7% 
7 

834 
8% 

3 




4 

7 

8% 
10 

9% 

7 

10 

10% 

7 
10% 

7 

102% 

7 

ION 

10% 

7 

10% 

7 
102% 
7 

ION 

10% 

ION 
7 

1013% 

7 

103* 

7 



Maximum O.D., Inches 



— XX 

<N CO <N 

to 



9 

9'% 

7 

9N 

9% 

7 



0% 

0% 

7 



l 1 




1 

02% 

7 
ON 

o 2 % 



3 




4 

7 
2 % 

7 

ON 
o 25 % 

7 

0% 
7 

2 % 

7 

ON 
0% 

oa 

7 

0% 

7 

oA 

7 



I I I 

<NCO <N 
LO 



7% 

723% 

7 
8% 

8% 
7 

8N 
8 3 % 

9 

7 

9% 
0% 

0% 

7 

ON 
o 2 % 

7 

0% 
7 

2 % 

7 
0^ 

025% 

7 

0% 

7 

2 % 

7 

ON 
0% 

0A 

7 

0% 

7 

ON 

7 



ESSE 

cc\ co\ co\ 
C^l CO <N 



5 

5% 

5% 

5^ 

5A 
5A 

6 
6 
6 

6% 

6% 

6N 
6N 
7% 

7 

7N 

7 

723% 

7 

8% 

823% 

7 

9% 
7 

9% 
7 

ion 
io 9 % 



io% 

7 

ion 

7 

lO 3 , 

7 



_-_ 

i i l 

CSJCOW 
LO 



3% 
4 
4 
4 

4% 
4% 

4% 
4% 

4N 
4N 
4N 
4% 

5% 

5% 

5% 

53- 

5M 

$N 
6 

6 

6% 
6% 

6N 
6% 

7 
7 

7% 

7 

8 

8% 

9% 
7 

9 8 % 

7 

10 

7 



c/jc/: 

i-H LO 



93-2 

9% 
7 

10 

9% 

7 

10% 

H 5 % 

UN 

7 

11^2 
11 

102% 

7 

ion 

10% 

7 

10% 

7 

102% 

7 

ioN 
102% 

7 

10% 

7 

102% 

7 

ion 

io% 

ion 

7 

1013% 

7 

ion 

7 



86 



ALUMINUM COMPANY of AMERICA « 



TABLE 37 



RANGE OF COMMERCIAL SIZES OF ROUND TUBING 

— Continued 



Thickness 



Stubs 

(•Mi] tr*» 



m • 

10 

11 

12 
13 

• * 

14 



Id 

16 



17 

IS 

■ « 

19 
20 

21 
22 
23 

24 
25 
26 

27 

28 

29 

30 

31 

32 



I nches 



.140 

.134 
.125 
.120 

.109 

095 
. 093 
.083 

.078 

.072 

.065 

062 

.058 

(14!) 

.040 

.042 

.035 

.032 

(128 

.025 

.022 
.020 
.018 
.016 

.014 
.013 
.012 

.010 
.009 



Minimum 

O.I). 
Inches 



CI 



He 

34 






Hi 

He 
Kg 

He 

He 

Vs 




Hi 




He 
to 

He 

He 

'ie 
He 

1 16 

He 

He 

He 



GO 70 



io 



/ / 

CI ^ 

I- 



10% 

7 
l 




7 

'"'% 
7 
l 




8% 

7 

7 
9 

7 
7 

8% 

5 
4 
4 

3H 

3 

2% 

134 



l 
l 



l 2 



Maximum O.D., Inches 



Z 
r. 

"I 






9>% 

7 

3 




4 



8% 

7 

8M 
7 

7% 

6^4 

<; :; . 

1 




1 

5 

3% 

2% 




* l A 
2 

He 

l 4 



5 .. 



EEE 

l i 
WWW 



10% 
7 

1034 

7 

9% 
7 

934 



8% 

7 

7 
9 

7 
7 

8% 

5 
4 
4 

SH 

3 




'4 

24 
134 



l 
l 



He 



EEE 
..'-'J' 



I I 



/: / / 

<N ro C4 
in 



io% 

7 

1034 

7 

9% 
7 

9M 
7 

8% 
7 
7 
9 

7 
7 

8% 
634 

5 
4 
4 

334 
3 

234 

is 

i 

i 

He 
3. 



chchth 

CI 

lO 



10% 

7 
l 




9 ] % 
7 

934 
7 

9 

7 
7 
9 

7 
8% 

5 

I 
4 

3 

2M 
234 

134 

l 
l 




He 



XXX 
www 



9% 

7 

l 




7 

934 

7 

9 

7 
7 
9 

7 
7 

8% 
6% 

5 

4 
4 

3H 

3 

2*4 

234 
134 



l 
l 



5 A 

He 

A. 



E-V 

l I 



9% 
7 

8?4 

7 

8 2 % 

7 

8>4 

7 
7 2 % 

6^4 

6h 






5 

334 

2 

% 
He 

h 

He 

i 




He 



87 



» 



ALCOA ALUMINUM and ITS ALLOYS 



TABLE 38— RANGE OF COMMERCIAL SIZES 

OF WIRE, ROD AND BAR 

2S, 3S, ITS, 24S, 51S, 52S, AND 53S 



COMMODITY 


SMALLEST 


LARGEST 




Diameter 
Inches 


Diameter 
I nches 


Round \\ ire — Drawn 


3(i ga. 


0.374 


Round Rod — Cold Finished 


H 


m 


Round Rod — Rolled 


% 


8 




Distance Across 
Flats. Inches 


Distance Across 
Flats, Inches 


Square Wire — Drau n 


Mi* Vn 


%x",, 


Square Bar — Cold Finished* 


HH l /2 


2 x -1 


Hexagonal Wire — Draw n 


16 


% 


Hexagonal Bar — Gold Finished* 


H 


1 7 K 


• >< 1 agonal \\ ire — Drawn 


Va 


H 


Octagonal Bar — Cold Finished 


% 


1 3 .6 




Dimensions 
Inches 


Dimensions 

Inches 


Square Kdge Rectangular \\ ire — Drawn 


1 in X 1 i 


h x " ir, 


Square Edge Rectangular Bar, Common 
\iloy — Cold Finished 


1 k x : ' s 


1 ) 2 x 4 


Square Edge Rectangular Bar, Strong Alloy 
Cold I hushed 


W|XH 


t 


Square Edge Rectangular Bar — Roiled 


v%*Vz 


3 x 10 


Hound Edge Reel angular Bar — Rolled 


. 09$ x 1 ] ,s 


HxG 




Dimensions 

I nch(5S 


Dimensions 
Inches 


Half Round \\ ire — Drawn 

Half Oval Wire Rolled 

Oval Bar — Cold Finished 
Half Oval Bar— Rolled 


y 4 x i 


% x Vk 

%L X : ' (6 

% x v K 

X x \'h 



*A few of the larger sizes are rolled. 

TWidthsupio 2.75 inch, provided cross-sectional ana is not greater than I 
square inches. 

The above table indicates the range of commercial sia Intermediate sizes 

are not all avadabl Table 27 for sizes of flattened wire and flattened and 

slit wire. 



88 



ALUMINUM COMPANY of AMERICA « 



TABLE 39— APPROXIMATE TEMPERS OF HOLLED BAR, 

ROD AND SHAPES— 2S, 3S, 52S 



Shape 



Diameter or Least Distance 
Across Hats (Inches) 



Rounds 1 
Squares 

Hexagons f 

( >ctagons J 



Hi^-t a n^les 



Structural Shaprs 



Up to Y± f inclusive 
Greater than %" to \W 
Greater than \y%" to 3" 
Greater than 3" to 8" 

fUp to y%" inclusive 
1 Greater than y % » to K" 
I Greater than W to iy 2 
Greater than VA" to 3" 

Standard Sizes 



Approximate Temper* 



Rolled 




y A \\ to hh 
y 8 n to mh 

kii to 3^H 

J/4II to ^H 

1 



Cold Finished 




HH bo J4H 

' Jl to i,II 



HB. to %n 

J^H to %\\ 
MH to HH 
^Hto^H 

J^H to %H 

y s n to kh 





Tempers shown are approximate. Minimum tensile strengths are not guaran- 
teed, but experience indicates thai the tempers shown for various commodi- 
ties may normally be expect ed. The small sizes tend to run harder than the 
large sizes, since the) finish colder from the rolls; also, cold finishing intro- 
duces a greater percentage of reduction in cross-sectional area, hence more 
strain hardening. Typical or average properties (not minimum) for the variou 

ullnss in the various tempers are shown in Table 10. 



89 






» » * ALCOA ALUMINUM and ITS ALLOYS 



INDEX 



Alclad products 31-33 

\nnealinjar practice 33-36 



B 



Bar 68. 70-72, 80, 88 

Bend radii 24, 58 



( 



I istings 



\Iloys — general. . . 
Die 



11 l 
SO 51 



Urn l- 1 lr(J 

Permanent mold 

Sand 

Design of. 
hoi i • of alloy 



47 50 
46, 4 7 66 

13-46, 64. 65 

51, 52 

17-20 



ommercial tolerances and sizes 

Sheet and plate— ull alloys. . . .75. 70 
Kxirufied producta 77 

"I iibing. ... . . 78. 79 

\\ ire, rod, bar all alloys 80 

Itolli-d gtructurai shapes 
Rough rolled round r-orner nquares 
and rectangle* 81 

Flattened wire and flattened and 

slit wire all JilloyB 81 

( immi tal sizes and forms of 

m;t i erials 



M ihCfllti lift JUH 






9 


Bar 






88 


Klatteued wire 






81 


Plate 






84 85 


Rod 






88 


Shoe! 


6| 


70- 


82-84 



Squares arjd rectangles 81 

Structui j*e» 

Tread plate Btretchet I 85 

T fc round 86, 87 

^ n 

( i imposition of alj 

1 He-casting 5(J 04 65 

Permanent mold nwrfing 46 66 
^and casting 43 



Conditions for heat treatment. . ,39 

Conversion factors 61 

Corrosion resistance 28-31 

Cost 6 



roug 



D 

Design stresses 

Factors for at elevated 

temperatures . . 60 

Die-casting alloys so, si 

E 

Electrical ronductn it \ 13 

Extruded products L7 f 22. 77 

F 

Forgings 21 

Forming 23, 24 

II 
Heat-treatable alloys 20, 21 

Heat treatment 20, 21, w 

1 > editions for 61 

1 Veci 1 »i ta tioo hea tHraetment 
praetfos , . . 37-39 

Solution heat-treat ment 

pract 36, 37 

I beory of heal treatment 39, 4<» 

Hoi forming 24. 25 



M 



Mechani I pro| I w - 

General IS, 16 

J'rr I amid alloys 66 

Sand cast » y* 04 65 



90 



ALUMINUM COMPANY of AMKK1CV « 



<c « 



Mechanical properties (Continued) 

Specifications 

Bar 68-71, 72, 73 

17S alloy products 68, 69 

24S alloy products 70 

51S alloy products, 71 

53S aUoy 72, 73 

Forgings . . 74 

Plate 67, 68 

Rod 68-73 

Shapes 68-73 

Sheet and Plate 2S, 

3S, 4S, 52S 67-70, 7 L 

Tubing 70 

Wire 68-73 

Chemical composition 

Die-casting alloys 74 

Wrought alloys 62, 63 

Modulus of elasticity 15 



N 



.Nomenclature 11 



x 



Plate 67, 69, 70-72, 75, 76, 84, 85 

Precipitation heat-trea tment 
practice 37-39 



K 



Rod 68, 70-72, 80, 88 



S 



Sand casting alloys 43^46 

Shapes, structural 17, 22, 89 



Sheet 



67 



Solution heat- treatment 
practice 



36, 37 



Specific gravity 13 



Squares and rectangles. ... 68, 70, 72 

Standard commodities, wrought 
alloys 55 

Strain-hardened alloys 16, 17 

T 

Temper designations 11-13 

Temper for bar, rod and shapes . . 89 
Theory of heat treatment ... .39, +0 

Thermal conductivity 13 

Thermal expansion 15 

Coefficient of 59 

Tolerances 

Bar 80 

Extruded products 77 

Flattened wire 81 

Plate 76 

Rod 77, 80 

Sheet 76 

Squares and rectangles 81 

Structural shapes, rolled 79 

Tubing, round and streamline 78, 79 
Wire 81 

Tread plate 85 

Tubing 70, 86, 8: 

W 

Welding 25-28 

Weight of alloys 61 

Wire 68, 70-72, 81, 88 

Wrought alloy 

Properties 17, 19, 20, 57 

Commercial forms 9 

27S-T 21 



91 



ALUMINUM COMPANY OF AMERICA 



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\LBANY, N. Y 90 State Sired 

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IALCOA 




I Ik word "Alcoa"' and the adjacent <!<-sigu are registered trade- 
marks applied Vj the product* of Aluminum Com pan ,f Amer. 
whose lech aJ staff exercises the most rigid control over <-very 
process io the production of Alcoa Aluminum . . . from the D <# 
of baunte ore to tbe production of uniform and hijrh quality aJu- 
ininum and aluminum alloys, in every o .rnmercial form. 



ALCOA 




-rtu \s \\ d ISM « 



|»m in I S.A